There is a general social approbation associated with behavior like that ENworld sanctions as "threadcrapping". Joining a discussion strictly to naysay is antisocial and brings people down. It also provokes arguments.
This particular instance is a little beyond some of the other ones, because some of the factual assertions in the OP were immediately shown to be objectively false, but once you chimed in with your negative opinions, they seemed to be based in part on statements of fact which had already been debunked. And it's an extremely strong temptation for most folks on the internet to argue with someone when it's a matter of demonstrable fact.