I'll start with one that doesn't seem directly related but correlates so closely that I can't help seeing the "tell" as a warning: putting "kappa" in a sentence like a punctuation mark. I've never seen an online conversation that started with that tell and didn't wander into final solutions and 14 words if it went on long enough. I know it's a :freeze-gamer: thing but it's not like there isn't already a wide overlap between :freeze-gamer: and :frothingfash: .
Admittedly the immagants part was, but I've met people that just like to see others suffer. They get a gleeful look on their face that's quite unmistakable.
(CW:Child abuse)
I once saw my ex father in law sit on my 10 year old step son with his knees on the kids shoulders and taunt him until the kid was screaming and he and his wife would just laugh and laugh while my ex just sat stoically. And naturally he was a chud/libertarian out in the boonies. He had a look on his face that is the same I see on anyone that likes that kind of thing. I see it on conservative politicians and religious and business people's faces every day.
Yeah, it's horrible. Same people will turn around and go "what about the Tsar?" 5 min later like that isn't a topic of anguished debate on the left about the necessity of violence.