Think about it. Being immune to death only makes that creature unable to ascertain actions that would harm them. Because they won't die from it.
They can do all the stupid shit in the world and it wouldn't matter because they won't turn dead from it.
They'll eventually realize they can get away with anything, and never bother to realize why they shouldn't do those dumb things.
Anything that's immortal only deserves to be isolated from everything else. They don't deserve to exist.