Calm down. In my mind, I did answer your question when I said that I am not against them. To be specific, I am not against the right to carry them, though I am not too sure that people like my paranoid son-in-law should have the right. I also like to see the weapon, so I prefer open carry to concealed. Just a weird quirk of mine. In states like mine, there are no hoops to jump through if you want to buy a weapon at a show, and it doesn't even have to be a gun show. You walk in, plunk down the money and walk out with the weapon. The state even passed a law that said that counties and cities cannot change that about any private or show sale. No registration is necessary.
It doesn't matter how powerful a single bullet is, when they don't carry so many bullets. If the gun is not capable of spewing out so many bullets that the shooter has a fair chance of shooting all the targets before reloading, there are opportunities to stop him. The fact that shooters often have time to reload pisses me off. People that are not willing to take that chance and would prefer to hide under a desk and hope he forgets them, are stupid, but I digress. According to Snopes, a ".223 SIG Sauer MCX semiautomatic rifle...is often outfitted with a magazine that holds 30 rounds, higher-capacity magazines are legal in Florida and reasonably easy to buy online. Other add-ons for the MCX — which is favored for its modularity, firing speed, controllability, and its ease of use." A weapon like this has no place in civilian hands, as it is not for protection, nor hunting. If you are armed and a lone gunman comes in, you only are shooting at one target. Why do you need an semi-automatic weapon to shot a single target? If you need more bullets, either the shot wasn't clear and you shouldn't have wasted a bullet, or you are a bad shot and are probably as dangerous to bystanders as the gunman is.
As for pit bulls, where they are illegal, you can't walk them or even let them into your own yard. Animal control will take them from you any time they are seen, and even enter your yard to take them. It is hard to own a large active dog that you can't take outside and that you can't let neighbors of visitors see because they may turn you in.