They can leverage these terms if they want to. For example you’re also only allowed to have one account per person.
Wasn’t it the Terraria dev who got his account locked and they used that as an excuse as to why he was locked out of his account? They said he had too many accounts or something?
They can enforce arbitrary rules when they need to if they wanna fuck you over; just like cops.
I have experienced the same login bug on the Mlem app as well. One of my devices stayed logged in and is working perfectly; my other device logged me out of lemmy.ml and I have not been able to log back in on that device.