Some objects are inherently dangerous, some are only dangerous when used maliciously. There are thousands of examples from both of those categories and in both categories there are legal objects and illegal ones. What decides if something is legal or not? You have to weigh it's benefit to society with the risk of it existing. Guns are not inherently dangerous but they do pose a risk, if you don't agree with that you are just being ignorant. But they arguably also provide some benefit, and that certainly isn't wrong either. Should they be legal? Weigh their risk and their benefit and decide for yourself.