That's not true globally; in the 20th century governments in Russia, Germany, China and Cambodia collectively killed over a hundred million of their own people.
>it makes them vulnerables to criminals and terrorists too. Which, so far in the western world, is definitely a much bigger threat.
Germany is the western world. Many of six million Jews would probably still be around if they'd been well-armed.
They had a literal military. This absurdist belief that something like the 2nd amendment would have ANY impact is literal propaganda.
Find me an oppressive government overthrown with private firearm ownership.