Of coarse when you hear stupid things, one tends to make assumptions about that person, lol
When I hear something off the wall, I tend to engage that person and try figure out where it came from. If there is more and I can tell that all this it is coming from this guy, I'll act like a bobblehead doll and boogie at the first chance.
What irritates me, is the guy repeating what he heard, overheard, or read, and is now spreading it unaware of the facts. This guy may stand a chance of you can set him straight.
I guess dumb crap does not bother me that much unless it comes from my friends, because they know better, or should know better, and now are going to know better.