Killing is bad... killing because you don't like $group is double-bad. Speeding is bad, speeding without a seatbelt is double-bad. etc.
If you are such a danger to society that you shouldn't be allowed to be armed in case of defense, then you probably shouldn't be in society and remain locked up. That's just my take on it. I feel similarly on taking away voting rights after prison as well. I may not like how you vote, but I'm just not a fan of taking away people's rights outside prison/jail.