The flyer is about vigilantism. That's not a right. It's against the law.
I think this needs to be justified. Nothing I read there seems to indicate it's vigilantism. Can you point me to those parts?
I think the fact that it's the KKK is clouding your ability to assess the flyer on its own. If that was posted by some local Mother's hobby group, you wouldn't see it as an excuse to provoke and execute minorities. I can't disagree with anything said on that flyer. But given it's a KKK group, I'd be extremely doubtful they'd follow the message of the flyer as intended.
And given that racists are, surprisingly, people too - just with different and understandably offensive views -, not some evil incarnate, we usually have more or less the same goals in life, eg protect our freedom, safety, livelihood and families. So I'm willing to entertain the idea that maybe, just maybe some of them want to protect their safety, families and livelihood. I don't like the apparent condemnation of anyone trying to take a neutral, purely skeptical stance, like WildCat received here.
I'm pretty confident the KKK will provoke people and start trouble. I'm also pretty confident nothing on that flyer is vile or unreasonable. Also, if I had people on my side protecting me and my family's safety against looters and rioters, I don't care if they're the KKK, Nazis or bin Laden family. But maybe I'm crazy

But as I said, I'm pretty sure the flyer is not actually representative of what the real actions of KKK will be.
And it's not an incorrect cite, it's a misinterpretation of the cite.
So what's the misinterpretation?
There is no law on the books in Missouri that allows you to get an armed posse together to go prevent trouble in some community.
We must have read a different flyer.