If so, can I please be allowed to have my own private nuclear warhead? I promise to only use it as a deterrent against a similarly armed government getting too "oppressive".
I promise not to set it off in a bout of drunken depression.
Sure, how about a howitzer then?
What you're failing to see or refusing to admit is that you too want to restrict access to weapons based on a certain threshold of collateral damage/body count each of them can inflict.
It's just that for some (perhaps most) of us, an AR-15 is way past our threshold.
As for the truck you mentioned that was used in France: if it's ever found that a certain truck model makes it particularly easy to run over people with, I bet my bottom dollar that soon after there will be legislation enacted restricting access to it.
Also good luck filling out all the paperwork. There's a difference between outright banning something and placing an astonishing number of administrative hurdles in the way. Private nuclear weapons come with so much paperwork as to be esssentially impracticable, but never the less possible.
At least that was the verdict last time I looked into the question.