The mall said no guns, but he defied that...so that makes him a bad guy.
In his mind, his entitlement carried more weight than the mall's policy.
Now if that's not indicative of a bad guy, I don't know what is anymore.
By bringing that gun into the mall that day, the message that guy sent to the world was that the rules don't apply to him and he can do whatever the fuck he wants.
BAD GUY.
Then I think most of us will forgive him because he erased the bad with taking out a murderer.
I'm not sure what the penalty is for flouting a private business's right to say "No guns here." At most they could just bar you from ever going there again, probably.