It's really that simple. I mean, boxing is a nationalistic sport or exhibition if you will. That said, race, ethnicity, and nationality are intertwined with boxing. That being the case you don't alienate the audience to the point of offense, and for a few reasons I can think of. For one, they might boycott and harm your business, see the Clippers situation. Broner's loss to Maidana was bad enough in itself an he's not proven himself nor worked his way to Floyd super stardom. In other words people arent going to purchase hoping he loses, and even worse people who may have been teetering, just might say mehh next time.
Another reason, is the potential for tension outside the ring. I was browsing online and came across posts indicating Blacks and Hispanics were getting into to it as a result of Broner's comments. The first thing I thought of was the Haggler/Minter fight. That fight was already racially charged being that it was a Black man vs a white man, not to mention an American vs a Brit. Then Minter made a comment about not letting a Black man beat him, which he said was misconstrued. Regardless those whites tore that place up after the fight, but the point is Minter contributed to the tension.
One other thing was the disrespect Broner showed by saying that sh!t. He disrespected Molina, he disrespected Mexicans in attendance and watching at home, and he disrespected himself but it's not like he has much self respect anyway. He's one of the worst examples of a buffoon that I've seen a long time. A couple posters stated that people shouldn't have been offended but if thats the case then why did he immediately apologize to Schaefer following the comments? I'll tell you why, it's because he was wrong for that, and he knew it. He knew he messed up, AGAIN.
, he just beat the fukk out of a MexiCAN. 
treatment next time around for that and blocking Matthysse from his endorsement moment the same night.