BS”D
You have to remember where this Jewish boxer is coming from, namely the FSU where sport is culturally very important – and where Judaism was kept under wraps until very recently. For someone of Salita’s background to be where he is today is a great kiddush Hashem, even if boxing isn’t culturally for us. He did not have the fortune to go to yeshiva or day school upon his arrival in the US either, making his situation an even greater kiddush Hashem.
Also, because he is not a heavyweight, his earnings potential is not all that great and I am sure that long before he suffers any damage, he will retire and either go into kiruv or into business.