I can agree, for hunting no. For the police or home defense, yes. An ar-15 doesn't facilitate it anymore then any other semi-auto weapon, and that itself would have a far harder time to get taken care of. It can be a pistol or rifle. I can't confirm this since idk how true it is, but a gun advocate coworker said any gun can be turned into a semi-auto. No idea how though, forgot what he said.
Point is, there are a lot of things that can facilitate that. Not just an ar-15. They are just targeting an ar-15 since it was recently used. Most people in the US though attribute it to a fully automatic weapon.