I read an article about that recently. It is a guy thing. Certain men admire a trash-talker. These men may be of any race, and they are often poorly educated. Whether from the Rust Belt, rural areas, or the inner city -- they have suffered misfortune Due to poor opportunities and inequities in society.
These men think trash-talking is a sign of strength, masculinity, and intelligence. Notice that most minority folks who support TFG are men. In fact, if you listen to these men or read their comments, you';; see this clearly.
These men feel like life has given them a raw deal. So they want to back a Champion with long coattails that are good for riding.
It's all a con, of course. But they don't want to think about that. They just want to feel better. It's all about the feelings.