My guy... have you been on youtube lately?
Ignoring for a moment that militias were actively prosecuted and pushed underground during the 80s/90s/00s, "guntube" quite clearly shows that there are organized and well equipped (how we say 'regulated' in today's parlance) militias out there still. They're just not registered 501c3 organizations. When the founders wrote the US Constitution, "militia" was every able bodied male who could muster arms. This is well established historically from the English tradition.
It isn't that we think gun-lovers are going to go ape-shit and shoot everyone around them, it is that a proportion of gun-lovers will do this. Which ones? Why you just have to ask them.
Why don't you do that, then? And look at the shooting death and mass shooting statistics and demographics, while you're at it. It isn't the people you're concerned that it will be, at all.