Since not all instances recognise each other, what you see will vary wildly depending on your home instance.
Also there is some self-sorting based on preferences and politics. Your instance (lemmy.world), for example, tolerates transphobes and zionists, and so attracts transphobes and zionists. (It may also gets blocked by other instances who don’t like this, so you won’t be able to see content there even if you personally are fine. This is one of the problems with lemmy.)
A couple of major differences from Reddit are:
Also there is some self-sorting based on preferences and politics. Your instance (lemmy.world), for example, tolerates transphobes and zionists, and so attracts transphobes and zionists. (It may also gets blocked by other instances who don’t like this, so you won’t be able to see content there even if you personally are fine. This is one of the problems with lemmy.)