What do you call a person who likes to blow up bars?

Answer 1

This person may often be referred to as a Saloonabomber.

Though, many people prefer to refer to this person as "Mentally unstable" or maybe, "A COMPLETE LUNATIC!!!!".

I hope this helps.

Answer 2

A person who likes to blow up bars would be considered a terrorist or arsonist, depending on the intention behind the actions.