Some gun owners seem to have this idea of armed revolution being a good idea, but yeah... Besides, the era where small arms alone were any good for that sort of thing is long gone. It's harder to get a ham radio license than it is to buy a gun in the US. Just think about that for a moment. Access to the RF spectrum is considered a privilege, access to weapons is considered a right.. Finally, it's sad that no one in the US mainstream seems to care about mental illness until something like a shooting happens
The Taliban has been fighting the U.S. military, the Afghan National Police, and the Afghan military for coming on 15 years with only small arms. They took a major city (Kondoz) within the last few weeks. I wouldn't be so quick to dismiss the power of an armed group. Not that anyone should want something so terrible as a civil war, but I don't think your argument is correct. The ham radio license is a very compelling comparison though. I wonder how effective a licensing system would be and what the qualifications to own firearms would be like in a system like that.
RE: licenses, a friend of mine pointed something out: sweden has a surprisingly large number of guns, but there has to be some kind of reason to own one. Usually some sort of club (hunting, pistol shooting, home guard). In other words, quite social and with a sense of responsibility. Not just "i want a gun".