US troll factories are just called social media. That's the one that tried to influence the Brazilian election in favor of the BolsoJr

Yes, many countries have them in some form or another. Their existence is not proof of anything.

In fact there is no proof about any impact. As someone who is online too much already, it is highly doubtful the impact is significant and there are more studies pointing to the opposite. High school teens to more impressive online raids if you say you dislike k-pop. Some claim there is a background effect, but anyway...

Troll farms have an interest to overstate their impact. Are you a troll? Easy accusation, isn't it?

Turns out people that voted incorrectly on issues like Brexit where quite focused on Brexit as a multi-faceted political issue. For example they might have objected to be called victims of Russian propaganda. Which is a statement on the level of tea leaf reading.