They weren't "disarmed" you absolute knob. "They" had guns and weapons and fought back against the nazis and lost. It turns out a bunch of civilians with small arms does not actually pose a meaningful threat to a state level military.
What makes this comment so obnoxious, aside from getting all the facts incorrect, is it helps promote this awful notion that you can be immune to state oppression if you just buy a gun. Shockingly, it does not work that way on real life. If you want the state to not oppress people you have to actually put in work to prevent it from happening, because if a state level military is coming to kill you it doesn't really matter how many guns you have in your closet or how cool your black temu tactical gear is. Artillery from 2km away will just kill you.
(Also as far as I know, when the vast majority of native americans died, they had plenty of guns.)