Why does the general attitude on Lemmy seem to lean toward more censorship and silencing of speech

Because "censorship" in this context is a weasel word. What people complaining about censorship really want, is the ability to be more openly racist, sexist, homophobic, transphobic etc. What people pushing back against that want is less bigotry.

But because the bigots can't own their bigotry, they hide behind "censorship" and not having enough "free speech".

This is literally youtube saying "The president says that hating on folks is ok, and we will make more money by aligning with that". It's not them taking a stance on free speech, because they still block stuff that costs them money. They still demonetise or block things that are supportive of LGBT folk for the flimsiest of reasons, none of which they would do if censorship or free speech were their reasoning.

This has nothing to do with "censorship" and everything to do with a deliberate attempt not to increase free speech, but to shift "allowed" speech to the right