Because they are not 'gunning' for the criminal. They are after sportsmen who compete peacefully with this firearm.
The antigunners love criminals but hate legitimate sportsmen.
You have greatly misjudged these folks. They're not out to stop you from having fun. They want to make sure that when they come to squash your "rebellion" - understand that your rebellioin will be trying to re-establish constitutional rule in the USA; something that has passed away long ago - they want to make sure you have a very difficult time stopping their armored vehicles.