I looked at UB1's user contributions and I couldn't find anything damaging that that user had done. Except for contributing to an edit war over whether there should be six stars on hir user page or not and blanking hir talk page. I don't understand why "UnbannableOne" is an unaccepted username, it's not like hir called itself "Administrator", "Root" or "JimmyWales" - any name that would actually make you THINK the user was unbannable!
I also think the ability to ban logged in users should be removed. It is way to powerful and all uses of that ability so far, has resulted in controversies.
BL