From all accounts, it sounds like an angry coach telling one of his players to stop playing music that drops the n-word all over. Peters says he immediately apologized and that this is not part of his value system. But it literally doesn't matter how racist he is or is not on the inside, if that's the only "racist" thing he's being accused of. Getting a player demoted because of it has already been denied by the Blackhawks. It's more likely Aliu spent more energy on "rebelling" than playing good hockey. Of course, him getting fired is a foregone conclusion at this point. I just want to hear more about the abuse allegations, as that is the real story in my opinion.
I'm guessing from your perspective of this you have limited experience of being an ethnic minority for any great length of time. Certainly the relationship with and cultural re-appropriation of the 'n' word by people of afro-Caribbean descent is an issue that should be approached as sensitively as that of issues of anti-semitism in its various forms.
I am and always have been culturally assimilated in the land of my birth, indeed with far greater cultural, historical and traditional knowledge than the vast majority of my compatriots, but I am often made very aware of my different skin tone, with a paternalistic or patronising attitude. Luckily, I am well educated, older and am by nature a forgiving optimist, and thus not unduly affected, but the 'difference' is nearly always 'in the room'. It would be much harder for a young black man, already an immigrant in a very overtly caucasian world.
While I am not a fan of historical trial by media, for a man in Peters position to be so utterly insensitve, stupid and provocative towards a young player who is already dealing with standing out like a saw thumb in an environment where he is overwhelmingly in the minority ethnically is shocking. What is almost more troubling is that Aliu was demoted that season despite performing to a good level (supposedly just after this incident, but that can't be corroborated), and that other players witnessed and complained about the comments without any action.
Even more worrying if it figures as part of a broader pattern of abuse etc.
Someone saying that a negative act of this sort they have committed is not part of their value system doesn't cut a lot of mustard with me when the act was a comparatively recent part of their adult life. In most work contexts, that phrasing would result in pretty much instant dismissal.