I think it is the realization that the society that they would claim to protect does not exist. Likewise saying what you like on the internet. A lot of people do not realize that it’s not like getting your say down the pub because the impact, where it is distributed again and again, magnifies and becomes greater.
Tbh if many of these racists had just kept this in the pub via commentary the law would struggle to touch them. Tech is clearly making the evidence and the impact much easier to prove.