Since we're talking specifically about the Second Amendment doing the "reminding", where are the mass casualties taken by the police and government forces by the armed militia?

I'll grant you that it's a protest, but most of the alleged violence described in that story seems to have been committed by the police. Peaceful protesters being beaten and mauled by attack dogs by definition don't count towards a valid argument for the effectiveness of the Second Amendment.

The protestors also lost - the pipeline was built, regardless.