I was just playing shiritori cat, and the cat played レズ! On the first day of pride month, to me, a lesbian, no less! I was very surprised it could do this. I'm not upset; I think it was funny as hell. That said, I'm not sure if it was an oversight that the cat can play derogatory terms/slurs like that, and I can definitely see it resulting in some situations where people are reasonably upset. Thought you should know!
This is definitely an oversight. Thanks for bringing it up! These restrictions were already in place for the communal shiritori. However, due to the way the word is selected in shiritori cat, the check was not added in by accident.