Let the garbage come on board; then we get to laugh at it, debunk it, roast the poster, and throw it into The Unicorn File.
Oh, and good things HAVE come from discussions on magnets! I still want an A.C.M.E. arm on the front of my car with a giant magnet on it for glomming on to semis...
But I agree about the conundrum of allowing that stuff to fester; Gassavers was overrun with HHO morons for quite a long time and I basically quit stopping in for a look because it had gotten so stupid in there. I think it killed the site.