What is the philosophy behind downvotes? Downvote non-productive/bad faith comments or downvote things you do not like?

Right, I think this was the potential concern I was vaguely remembering.

I also see these when sorting by All in lemmy.world, for instance (no pun intended). I'm just making sure I am not confused. Sorry if I confused you in the process!

So what is the point of congregating on a general purpose instance? I ask this because of the snippet from the root comment:

The problem is that users tend to go where other users are (otherwise why go there)

If everything is visible from any (federated) instance, why not switch once you encounter slow down? In my comment, I was just clarifying that I understood the premise.

Would this require you to switch between instances to view all the content you wish to follow? That doesn't seem very appealing as a user.