Freedom mean you can't tell me what to do
Freedom, often, is good. I know, brave statement. But, we place limits on it all the time. One obvious example is nukes.
Most people think it would be a bad idea to give everyone a nuke, even thought the simple act of ownership dose not in it's self negatively impact everyone. The consequences only happen when someone break the "your freedom to swing your fist stops at my nose" principle and blow one up. A threat we obviously see as too big to allow, so no nukes for you an me.
The same principle can be taken with guns. We already limit guns to people we deem likely to misuse them with red flag laws (although fans of the the freedom argument aren't necessarily a fan of red flag laws). Perhaps a better example is drivers license. We limit peoples freedom to drive in order to improve the safety of everyone, increasing general welfare.
Getting ride of guns is a continuation of that same principle. The burden of proof is always on the person who wants to infringe on a freedom as to why its justified, but in the case of guns, tools of murder, the reason seems to be fairly self evident.