There is no place for racism in sports. The coach must all players make feeling safe and even if 18 guys laugh and only one feels offended it is still not OK.
I would like to ask what kind of racism it was? It is never OK, but to me it is different whether you say something like Asians can't drive/white guys can't dance or whether you use really evil stereotypes (like black people are thugs...) or even slurs.
The former shouldn't happen too frequently either but I think it can be overlooked if it occasionally happens but the latter shouldn't be tolerated even once.