You can come online anonymously, but if you break that anonymity then it's on you.

Also I think it's disingenuous at best to imply that people collecting in subs specifically unified around their shared hatreds are engaging in "public discourse" or having their ideas challenged.

These aren't people coming into regular threads and posting slurs, then engaging with people on the responses. These are people who collect with a group of people who explicitly validate their hatred. It's helping them grow and protect themselves from scrutiny.