My solution is to make all US flags out of non-flammable materials.
Protestor: We're going to burn the American flag! Down with America!
American: You can't burn the American flag!
Protestor: Freedom of speech!
American: No, I meant, it's not physically possible.
Protestor: Fuck you! *tries to light flag* Why won't it ignite?
American: TROLLFACE
Protestor: Goddamn Americans!