Personally I think the issue with threads on politicians is that 99.99% of politicians aren't funny, not in the way, to the extent or with the regularity of a proper lolcow. Most proper lolcows are too dysfunctional to achieve mainstream success in politics - at best they enter local politics (Vordrak, Aimee Challenor), or they try for the big time and flame out in spectacular and entertaining fashion (Wu, Sargon). Trump is a very standout exception, he keeps up a solid flow of idiocy and unintentional funnies in a way that no other politician I can think of ever has. I think the key is that Trump would be a cow even if he didn't enter politics. He's a natural buffoon who causes chaos wherever he goes. His getting elected president was lightning in a bottle (unless someone like Kanye West ends up elected in future, I guess).
Other than Trump though, I don't think that threads on politicians are in general a good idea. I have seen at least two attempts in PG at threads on British Labour MP Diane Abbott. But the problem is that whilst Diane Abbott is terrible, she isn't funny. She's not entertaining, she's infuriating, and almost all politicians with weird opinions or dysfunctional lives tend to be. The reason we can laugh at cows is that ultimately, they don't matter. They're not in charge - Jake Alley or Roy Phillipose can scream their dumb opinions into the void and nobody is going to pay attention to them. The pathos of that is in itself funny. When someone with equally terrible views achieves power, it's not funny any more because they have the ability to ruin the lives of millions of people. This is a site for comedy and laughter, not anger. Threads on politicians will just descend into A-Logging because, well, it's justified to hate a bad politician, because they can harm you and many others. Plus threads on politicians attract political spergs and suddenly the culture of the site changes into just another polarised political rage pit.
If I want angry, serious politics I can go literally anywhere else. I come here to laugh at idiots.