A Fulham FC fan living in California is suing a state agency after he was banned from having the letters COYW on a personalised car number plate, as they feared the slogan "Come on you whites" had racist connotations.
University professor Jonathan Kotler said he was "shocked" at the decision.
Launching his legal case, he claimed the decision by the California Department of Motor Vehicles violated his right to freedom of speech.
"It's just a shirt colour," he said.
"The people at the DMV are either extra thick or very PC."
Prof Kotler applied for a plate that would read COY-W - an abbreviation of the slogan commonly used by Fulham football fans - and a hashtag seen every weekend on many Twitter posts about the club.
The 73-year-old, who was born in New Jersey and now lives in Calabasas, California, has been a fan of Fulham FC for decades, after watching a match "by happenchance" during a visit to London.
He was originally a fan of both Manchester United and Fulham, but chose his current allegiance in 2006 when both teams were in the Premier League.
Prof Kotler, who teaches media law at the University of Southern California, put in his application for the number plate last year and had to include the reasons for his choice of letters, but it was turned down.
The Department of Motor Vehicles said the COYW slogan could be considered hostile, insulting, or racially degrading, according to the US federal legal case.
"I sent them tons of material," Prof Kotler told the BBC. "Press releases, stories from the British media, letters from the chairman who uses 'come on you whites'.
"I pointed out that many clubs in Britain are known by their colour - the blues, the clarets. Nobody thought the Liverpool reds were communists."
He added: "Even when I did it, it was the furthest thing from my mind that anyone would object to it. I was shocked, absolutely."
'This is crazy'
He said the club's owner, Shahid Khan, "uses the phrase all the time".
"Half of the team are non-white. And it's just a shirt colour. It's got nothing to do with anything other than that.
"I decided this is crazy, this is enough. I can take it up to a point but this became personal."
Prof Kotler said he travels to watch Fulham play in Britain on average around eight to 10 times a season, often taking the 11-hour flight on a Thursday and returning back in the US by Tuesday ready to teach his students.
In his legal complaint, he is asking the court to declare the DMV's criteria for personalised licence plates unconstitutional. He claims he has been deprived of his right to freedom of speech.
The Department of Motor Vehicles says it does not comment on pending legal cases.
California's number plate rules
Plates will be refused if they carry any configuration deemed "offensive to good taste and decency", including:
- sexual connotations, or terms of lust or depravity
- vulgar terms, terms of contempt, prejudice or hostility, insulting or degrading terms, racially or ethnically degrading terms
- Swear words or terms considered profane, obscene or repulsive
- configurations with a negative connotation to a specific group
- configurations misrepresenting a law enforcement entity
- foreign or slang words, or phonetic spellings or mirror images of words falling into the above categories
The number 69 is reserved for cars made in 1969.