You’re Canadian, so I’m going to spoon-feed this to you. Cars can only be driven when registered, insured, and piloted by a licensed, demonstrably competent individual. The right to pilot a vehicle can be taken away if the pilot is no longer demonstrably competent for a variety of reasons. None of those things is true with assault rifles. If you’re over 18 and have money, you can get a big ol’ boomstick and all the ammo you can carry. Your “strict screening and responsible ownership” is exactly what a very loud portion of the American population is vehemently against, and the reason why those things don’t exist here.