Users from all other instances can view these posts and comment on them. I think the main point of choosing a server is that your local page will be more relevant to you.

I’m following 6 communities right now, 4 of which are from different instances because they just don’t exist on beehaw yet.

Luckily from my experience Mastodon and Lemmy have both been very pro LGBTQIA+, probably because the haters can barely use the internet in general lol