Not very. Note my hedging in mentioning "capable" people :-)

I think that in the short term there is the incentive to pile onto the stupid post and shred it to bits. But the bloom on this flower fades very rapidly. Smart people tend to realize that it's not a good use of their time.

Contrast this to a nonstupid but controversial position which motivates someone to write an excellent piece -- for an example consider Yvain's anti-neoreactionary FAQ.