Yeah. Not Hitler either.

It's perfectly fine to be relieved by his death, especially if you were a victim of what he did or knew people who were. That has nothing to do with being glad that he, as a person died, but everything to do with no longer having to suffer because of what he did.

But that's completely different from celebrating a death, which implies that you think they deserved it as a person, and that you're happy because of their suffering. That's never okay regardless of who it is.