You'll have to forgive me, because even after you explained it, I still don't understand.
If someone has a link in their signature pointing to an unassigned user name, then grabbing that username could also be interpreted at plugging a security hole as a stop gap measure while the problem is being discussed.
I don't see how it's outrageous. I don't see how you overstepped your bounds.
I think the context is important (it's hard to dig up the edit history for so long ago). I actually was in the wrong about the way I went about things - it was being debated and I really did try to prove a point (though it never occurred to me that I was being disruptive).
The editor in question quite possibly had good intentions, or didn't see anything wrong with what they did. Whilst I was not a malicious actor, there was debate about the situation and I think people objected more to the way I went about proving the point I was making (which I maintain was valid). That's a fair cop, and I accept my action was rash.
If someone has a link in their signature pointing to an unassigned user name, then grabbing that username could also be interpreted at plugging a security hole as a stop gap measure while the problem is being discussed.
I don't see how it's outrageous. I don't see how you overstepped your bounds.
It's not clear to me what happened here.