https://www.ucsf.edu/news/2014/01/111286/access-guns-increases-risk-suicide-homicide
https://time.com/6183881/gun-ownership-risks-at-home/
It makes sense, more proximity to a weapon is more potentially deadly encounters. An intruder very rarely enters your house, but you pass the gun safe in your closet every day.
True, and I'd agree on the civil war point.
If you're prepping for an invasion your best bet would be supporting wartime mobilizations instead of personal defense. Bootstrapping a total war economy is no joke.
Your government can probably handle the logistics of recruiting/arming/training people better than local defense cells. However, even if you're not enlisted they'll still need people to work the factories, drive the trucks, sell war bonds, etc...