Well, one of them came to our front door a couple of years ago (our neighbor across the street, knowing our political bent directed him to us.) I think the Campaign du Jour was the "mercury poisoning" by Holtra Chem.
One of us (probably me) dragged him into the house, shoved a copy of the U. S. Constitution into his face and held him captive for about half an hour.
When queried on any of the specifics of his particular grievance, he was predictably vague."The poison is in the dose" argument seemed to be a really vexing one to him.
He wore a red kerchief on his head, just to drive the point home.
Bill