[imardmd1]

So what happens when people aren't afraid of them, and simply shoot them down where they stand?

That's not going to happen right away. The point is that these activists want to destroy a culture in which people act in such a way that you can leave your front door unlocked, even when you go away for a vacation, and count that it would be a very unusual thing for someone even think of trespassing, let alone do it. By infiltrating unprincipled followers, they have achieved what they set out to do.

And we let them.

[metmom]

Sadly, true on all accounts.