Pretty sure they understand it well enough. It's more a matter of eroding resistance.
From what i've seen directly i blame the NRA for a decades-long campaign to recharacterize our responsibility to be ready to spontaneously form local militias against threats internal or external, as the right to kill animals for fun.
And the central government with its standing army and pet bankers etc don't want us to be either educated as an electorate or armed as potential militia so they pretend they don't know what words mean and most of us are illiterate enough to buy that bullshit.
Hey wow nice earthquake hit right now. Sweet.