If MacBook Air owners were stupid enough to go onto the MacBook forum and start a thread such as
"12-inch MacBook, the worst ever, don't buy it" with no real substance behind it (much like this thread) then yeah, I'd consider that trolling and would expect 12-inch MacBook owners to respond in kind.
As for owners defending their purchases... hell yeah, a lot of people do. We've all put a good amount of thought into our purchases to make the choice we did. To have some idiot on either side cross the fence and bash product X with comparisons to product Y of stuff that doesn't even apply to everyone and call it "the worst ever", is low class and should be dealt with accordingly.
Me, I love my 11-inch MacBook Air. I love it so much (even the screen!

I know right?) that I simply enjoy it and don't feel any need togo onto the 12-inch MacBook forum and start trash talking threads to justify my purchase. Who knew life could be so simple?