Having tried all three, its a stark difference in how much more social Lemmy is comparatively. Its not even close. Almost all posts I've encountered on lemmy have interaction; whereas, more often than not, posts on the other two platforms have no interaction. Wonder what the driving factor is behind this difference?
There actually are those instances, they are just broadly defederated, lol.
There are definitely people that make accounts elsewhere to "engage beyond the wall" so to speak, but Hexbear and Lemmygrad for example exist for their own users, not as a "base of operations" for widespread brigading like some claim. It's nice to visit spaces free from liberalism and constant arguing, as a Marxist-Leninist myself. I also think the "screaming" type of behavior is more frequently found on liberal instances than leftist ones, but that's anecdotal and I have no way to prove it, other than the suggestion that perhaps our implicit bias clouds what we percieve as civil and what as "screaming" in the context of comment debates.
See I don't mind a decent conversation with them either. I actually hold a lot of 'leftist' views myself. What gets to be troublesome is when people come in with a perspective that what passes for liberal in the US is violently evil. Our system is very flawed, easily viewed by the way the electoral college allows for a person with less of the popular vote to win. However, it's what exists and without some massive uprising changes are going to be slow at best.
Look at the chaos that came from the George Floyd murder. That went on for a few months and little of major note changed. Or the occupy Wall Street that just kind of petered out to nothing. The media moves on to the next shiny thing and people lose interest. The most recent with the killing of a CEO was just a couple weeks ago and you can already feel the fervor for it slowing down.
People have good reason to want changes, and so many times 'liberal' and 'leftist' people have similar stated goals. It often feels that the liberals are being fought from both sides, one actively against them in principal and the other yelling for trying to work with the system as it exists.
Liberalism is the dominant system, though, and revolution is still the only way we will be able to get meaningful change. Liberal identifying people can be disillusioned with the system they perpetuate, but have yet to meaningfully change the system. Leftists globally have a much better track record at getting change.
A big part of it is Americans at large object to any kind of coercive governance however it manifests. I can't in good faith say that nations like China or N Korea that exercise such tight control over the public media and messaging are a net good to their population. Cooperative social goals for universal housing, healthcare, a decent standard of living are good, but we have a huge portion of 'bootstraps' minded folks that get in the way. In the meantime we get this piecemeal patchwork that we have that over time has lent itself to rights for minorities of various stripes that eventually get adopted as the norm. Right now we're sitting at a spot where the pendulum of progress is being pushed hard back right, how to stop that is the tough question.
Over 90% of Chinese citizens approve of their government, regardless of what you believe about their system they seem to enjoy it. You should listen to others outside the west more.