I don't necessarily think Human was targetted because mafia knew his role - if fact, I think it was totally coincidental. I think a person is usually targetted because of a)their role or b)their knowledge/scumhunting abilities. I've been in several mafia games with Human enough to know that he can be a total pain in the arse for the mafia if kept around long enough. So yeah, he was probably targetted for that reason, or it could have been a totally random kill.
And I never even heard of a tailor until now. ;_;