There is hypocrisy in public (and, for that matter, private)life. In other news, the sun came up this morning. This is said in no way to lessen the offense; I only mention it because in any discussion of values and principles an example of another person who seems to be 'getting away with it' can be cited. I don't see that arguement as advancing the discussion. (Particularly with regard to politicians. They get fired by the voters --- it's not a parallel example.)
I've also never much cared for the "we don't know the person" point. I doubt any of us 'know' (or knew) any sitting President, for example, but I'm sure we all have opinions about them. None of us knew Jack the Ripper, but we'd all agree he was a bad 'un. I've never seen Australia, but I know it's there. The discussion isn't whether the coach is a good person or bad; it's whether or not he should have kept his job after his comments. Apparently his employers, who did know him, felt that his resignation was apropriate.
It doesn't take a rocket scientist to know how that word is regarded in our country. Anybody who uses it, does so at their own peril, and the institution for which he worked found it unacceptable. He didn't have a right to that job no matter what. He chose to cross the line, in front of known members of the press, and defend it as the vernacular of his players. (One can only hope his imitation didn't extend to low-slung trousers and a proclivity for amplified base in his car.)