I could have sworn I've heard Americans insisting for years that there was an amendment specifically for situations like this, but what do I know. I'm sure doing nothing and expecting the situation to turn out fine is a reasonable course of action.
I would say a majority of Americans are living paycheck to paycheck and don't own a firearm, so yes, not really representative of "Americans just letting it happen"
Before then there are local protests and meetings to push legislation, as well as federal representatives to contact. If you're looking for something a little more immediate and dramatic, you might enjoy the guns, but frankly the organization around them is kinda iffy.