I think a lot of people are just out to get you goat. They want to piss you off. I think all of us have dealt with a similar type of person as we go through life, but that's usually just in normal conversation.
You're putting out stuff that stays there for a long time and so those Jackasses have a long time to formulate their stupidity. I agree, the best thing is to ignore them. Sometimes things are so infuriatingly stupid it can raise your ire very quickly so stop and take a breath or two, grab a beer and let it roll off your back instead. There are times I've had to do that and it's really, really hard. 'em.