I've observed the opposite, but left it's a broad paintbrush, best to use six or nine point political axes.
Lemmy seems to get a lot more diverse comments, I see less uniform anti capitalism sentiment for example, lots of folks seem to be more Libertarian than Auth Left for example.
I've also seen a lot more pro free speech people, and dissenting opinions too, so since the current left trends towards limiting free speech, this also feels different than Reddit.
This is my observations, it may not be true, but it's my impression.
I'm not sure if you're talking about the left on a world wide scale, but in America I really don't think it's fair to say that the left is the side limiting free speech. Sure, they may paint the use of certain words as distasteful, but that's basically the extent. Leftists don't even tend to get the law involved outside of defining what may or may not be hate speech.
On the other side of the aisle, the right wing party is promoting book bans and firing teachers they disagree with. Several states have a version of the "don't say gay" bill that literally prohibits teachers from explaining why one student has two dads, and a similar bill that prohibits institutions from simply acknowledging a kid's preferred name. Texas and Florida are defunding colleges with curriculums they as a party don't like. Louisiana (along with a few other states) passed a bill requiring you to prove who you are with state ID before you can view something they deem inappropriate.
All of those things are actual examples of infringing the concept of free speech. Does the left do anything remotely like those things?
It's the conservatives that ban books, not the left of the right. It's the same in the USA, but for example we have a very conservative communist party (obviously - they want to return to what they think were good old days, but like the GOP across the pond) and a progressive right-wing pirate party that's largely made up of rich young techies, so leaning right economically but currently pushing marihuana legalisation.