Everyone can be self centered at the same time. Not sure why you think that wouldn’t be possible.

I guess you're right.

It hard to see why you expect that the “Admins” would be able to prevent anything they don’t prefer so casually.

Well, think harder. They're admins, not peasants.

It would be nice if the software allowed for many more things but it is limited, development is slow, and prioritizes what they get funding to work on.

That's a red-herring.

If you look at the issues list, you’ll see that there are many desired changes, so the current release is not how the developers intend it to function.

But then, this is a good idea, and I'll do this.

If I were an admin a lemmy instance, I would not consider it fair game to downvote a post on a community that you’re not subscribed to.

But then, there would be admins who would be okay with it. As long as the platform allows it, it's fair game. Unless admins use a workaround, like banning the users who do this - but they're not doing this either, are they?