Some instances disable downvoting. Is this intended to be for communities on that instance or users on that instance, or both?

I noticed while reading Memes@lemmy.ml ( https://reddthat.com/post/2053 ) that some commenters were talking about being downvoted, but I have no downvote button. Because downvoting is disabled on my instance?

How does it work the opposite way? Are users from lemmy.ml allowed to downvote on posts for example beehaw (who also has disabled downvoting)