A big problem the communists had during Tiananmen Square was that PLA units were generally assigned to the localities that they drew their soldiers from. So Beijing was covered primarily by Beijinger soldiers. This was problematic because it turns out they didn't want to shoot their own, so they had to bring in PLA units from far away before the crackdown could really begin in earnest. They corrected this problem by mixing up units (so PLA units are stationed from places far away from where the soldiers were sourced). They also added actual riot police in the form of the PAP so they didn't have only PLA soldiers with tanks to put down internal insurrections.

As far as resisting "government" in a democracy, it is much more likely that one side of an ideological divide wants to subdue the other (or both want to subdue each other using force). More like Republicans vs. Democrats and not really the people vs. the US military. One person's terrorist is another's freedom fighter.