Most sites have rules against offensive screen names. If it bothers you, email them about it. They'll probably ask that the player change his or her name.

Even though you're playing against adults, most sites use some sort of filtering software to block offensive chat (kind of silly imo as long as words aren't being used as verbal abuse). If a screen name slips by that would otherwise violate a site's standards (even the spirit of their standards) , it hurts nothing to let them know about it (it's their business decision afterall). If adolf doesn't like it he can crawl back into hell where he belongs.