I wont even go into this from a moral standpoint, just professional. You cant say nigger, faggot or kyke in any public setting when you are a walking representation of a brand period. All NFL contracts have code of conduct clauses becasue the players again are walking representation of the brand. Kobe got a big fine for just slipping the word faggot at a straight man and got HYUGE media flak.
Dont compare this to arrests for crimes or violent nature, compare this to another industry under the same circumstance to make it apples to apples. I for example run a brand for my parent company. I am the face of that brand and within the subsegment of the industry I am in, my name and person = this brand. If somehow a trade news website or magazine publishes me dropping an N bomb recorded, you bet your ass I expect to have some severe repercusions from my employer.
A side note to your part about why cant white people say it: The same reason why I can say kyke and you cant. For me to say it decreases the power of hate that it represents. For a non jew to say it, empowers it because it is said with intent to harm, hurt or derogate.
Side note, anyone else think this was really stupid considering he plays the MOST VULNERABLE position in the NFL and I can only think of one white starting DB in the league. He needs to be worried more about losing his spleen from a violent hit than his job.