Idiot right-wing gun-lovers who actively support the kind of fascism we need to be fighting aside...
The idea isn't to fight tanks and jets with rifles head-on. The idea is that an anonymous armed insurgency is really hard to defeat. Anti-armor vehicles work great against armor, but trying to use them on small insurgents made up of random individuals is like swatting a fly with a sledgehammer: you do a lot of collateral damage but the actual target is fine.
Overconfidence in stealth jets and aircraft carriers is why Iraq and Afghanistan turned into decades-long engagements before we'd just gave up and left. The regular Iraqi army was defeated in under 2 weeks, but we still lost the war.
And if it were to happen here, the government would also have to worry a lot more about troops unwilling to kill fellow citizens, unlike in the middle east where they were all strangers speaking a different language.