I joined Lemmy during the great Reddit exodus and I’ve been here pretty much since then and to be honest, I never really felt the difference between the two except user count, so it’s interesting to hear other people’s perspective such as yours.
As to your last point, I think there are a lot of factors, anonymity being the biggest one. Lack of social contracts being another. It’s easier to be a jerk behind the screen where you don’t have to actually face the real-life consequences of treating people poorly. Compound that with others who encourage and join in on the hate. Sometimes, it’s deserved, though more often than not, it isn’t. That’s just my theory, though.