We don't allow it.
This is a family site. There should be no reason at all to be abusive or offensive.
We have alot of members here who bring their small children onto the site to learn and play chess and they don't expect to be subjected to abusive language, but that said the site is designed to appeal to a broad audience.
With over four million members, hoping that they all abide by the ToS is a long shot.
why does chess .com allow certain players to use foul and abusive language my grandchildren watch while i play and i dont want them to see this