I had this happen to me. Some anons once brought up some legit criticisms of a person in one of my games but also made some (imo off-topic and uncalled for) jabs at the person's irl appearance and weight.

I responded agreeing that the person was a terrible person and a crappy RPer, but that I didn't think their weight was relevant and felt like we should keep everything purely focused on their RP (which I agreed was bad) and their personality (which I agreed was entitled and shitty).

I was promptly called a "whiteknight".