Adriano Galliani vowed to appeal in “every possible seat of justice”. He would make his case first to the Italian Football Federation’s disciplinary committee, but was prepared to carry this fight on into the criminal courts if necessary. The Milan vice-president could not back down over what he considered an inalienable human right: the right to insult a group of strangers.

On Monday, Galliani had been informed that his team must play its next game, the one against Udinese on 19 October, behind closed doors. Milan were being punished for the behaviour of their fans during Sunday’s 3-2 defeat to Juventus in Turin. Football federation observers had heard a number of the club’s supporters singing derogatory songs about people in Naples, claiming, among other things, that the city’s residents all had cholera.

The group responsible for these chants was small, a few hundred people at best. Their ditties were not loud enough to be picked up by TV audiences watching at home, and most people at Juventus Stadium will have been oblivious, too. “No TV station and no newspapers heard them,” said Galliani. “Maybe the observers heard them in the toilet or at the bar.”

It was not just the small size of the mob, however, that rendered this verdict contentious. What made Galliani most angry was the fact that Milan were being punished under the same rules that the Italian Football Federation used to fight racial discrimination.

Those regulations were updated this summer, following the introduction of Uefa’s new disciplinary code. That document lays out guidelines for all member associations to follow in areas ranging from player behaviour through to the maintenance of public order.

Article 14 covers “Racism, other discriminatory conduct and propaganda”. It states that punishments should be handed down to any team whose fans “insult the human dignity of a person or group of persons by whatever means, including on the grounds of skin colour, race, religion or ethnic origin”.

That is unquestionably a broad definition. A person of a more sensitive disposition might ask whether it is not insulting to one’s human dignity to stand in front of tens of thousands of people while they laugh at you for failing to kick a ball into a net from a few yards out. We all know that during football games, things get a lot worse than that.

Individual football federations have been left to clarify their own interpretations of these laws.

Article 11 of Italy’s rulebook states that: “Discriminatory conduct … is defined as any conduct which, directly or indirectly, causes offence, denigration or insult on grounds of race, colour, religion, language, sex, nationality, ethnic or territorial origin.”

The crucial words here are the last ones. Milan’s supporters – or at least the small number of them involved in the chanting – were indeed insulting their rivals because of their “territorial origin”. The observers noted that they had also run through several renditions of a more mild chant whose chorus simply ran: “We are not Neapolitan”.

Galliani, though, was never contesting the letter of the law. Rather he was making the case that the law is an ass. “’Territorial discrimination’ exists only in Italy,” he said. “Uefa talk about racial discrimination, but we’ve invented this territorial definition all on our own.”

Italian supporters are hardly the first to take aim at their rivals’ home cities. In fact, such insults are a staple of just about every major league in Europe. As Gabriele Marcotti noted in a recent piece for ESPN, the Premier League has plenty of obvious examples. Fans from Liverpool are mocked as thieves and crooks at just about every away game they attend.

The question raised by the verdict against Milan is whether such insults should be treated as seriously as racial ones. “For a long time the stock answer was that abuse based on race, religion or sexuality needed to be treated more seriously because it was predicated on real and pre-existing discrimination or power relations,” wrote Marcotti. “Some people don’t find that a satisfying explanation. Personally, I think it’s a pretty good criteria to apply.”

That opinion is shared by the Napoli supporters themselves. During the team’s win over Livorno on Sunday, Ultras at the Stadio San Paolo showed support for their counterparts from Milan, mocking themselves with an enormous banner that read: “Napoli [has] cholera and now you should close our curva too” (a move which brought echoes of recent arguments in England over Tottenham fans’ right to call themselves ‘Yids’).

They were not the only ones to put on a show of solidarity. On Tuesday a group of Inter Ultras released a statement offering support to Milan, even though the Rossoneri remained “our most bitter enemies, who, ever since we were little, have let us understand the words ‘hate’ and ‘grudge’”. The Inter fans vowed to engage in discriminatory chants at the next home game, and called on all other supporters to do the same, “so we can have a Sunday where every single stadium is closed.”

It did not take long for others to fall in line, with Ultra groups from Juventus, Genoa and Brescia all promising to do the same. Regardless of the animosity they might feel towards their rival fans, all had been united by a shared resentment of the stance taken by the powers-that-be.

Their actions have put the national football federation in a difficult position. Should it reverse or soften the punishment now, it will be perceived as giving in to the Ultras – making it harder to impose strong decisions in the future. One Milan supporter who claimed to have taken part in the chanting even gave radio interviews this week stating that his group had sung those songs precisely to force this situation.

On the other hand, polls conducted by national news outlets suggest that most people consider the punishment against Milan to be excessively harsh. Even the Serie A president Maurizio Beretta has spoken out against it, writing a letter to the federation requesting that the rules be revised.

The truth is, though, that the notion of ‘territorial discrimination’ is not a really a new one. It has been listed alongside racial discrimination in the Italian federation’s rulebook for some time, even if it has not been interpreted consistently by the observers that go to games.

Instead what changed were those Uefa guidelines – and specifically their instruction on how discrimination should be punished. Previously in Italy, a club like Milan might have received a token fine, which they would likely have paid rather than waste any time protesting.

But the governing body’s updated rules set out a firm list of sanctions for national federations to follow. First instances of discriminatory chanting by a team’s fans should result in a one-game closure of the section of the ground where they began. Second instances must be punished by forcing a team to play its next fixture behind closed doors. Any further instances can lead to points deductions and games being awarded to the opposition.

Milan had already been sanctioned once this season, for the behaviour of their fans during the game against Napoli at San Siro in September. Similar songs about cholera were sung, along with another chant imploring the volcano Mount Vesuvius to “wash Naples clean with fire”. And the Rossoneri were indeed obliged to close the Curva Sud, where the chants originated, for their next home game.

By ordering Milan to play the next game behind closed doors, the Italian football federation are simply following the Uefa regulations. Those are not up for discussion. Any hopes of Milan winning their appeal, therefore, rest entirely on their ability to re-open the discussion in Italy about which kinds of prejudice should really be defined as unacceptable.

“Our regulations reference discrimination. They not specify what it can mean,” confirmed the Uefa president Michel Platini on Wednesday. “The individual case goes to the disciplinary body that is evaluating the situation … federations are free to expand the field and add new types as they see fit.”

A decision on Milan’s initial appeal is expected on Friday. Even with the international break, they could not really afford to leave it any longer. They will doubtless wish they had more than a few short days to work through an issue as complicated as this one.