There's obviously a strong leftist culture here

That depends on what instance you create an user on. For example, Lemmygrad.ml and Lemmy.ml are not the same thing, despite both belonging to Lemmy. The issues I see are having a tankie culture, and not having more points of view.

There are less users so less content

That's something we can help with, although it's not so easy. I mean, the users that are already here, we can create more content and interact more with each other, so eventually more users will come. It can be boring and tiring, but it's not impossible.

Federation is a stumbling block for many people

That's something absolutely new for the vast majority of people. I felt myself confused the first time I joined the fediverse too. But after some time, I felt myself less confused. Some clarifications, tutorials and support can do the real trick.