They don't know. They just find any reasons to support what's happening. Hindsight is 20-20.

So how is this responsible journalism?

It reminds me a bit of web 2.0 bloggers who need a news angle to mention a startup no matter how weak/silly that news angle might be.

Watch out for pump-and-dump schemes on tootsie roll pops.

By the way, this might be the strangest sentence I've ever written.

In a few cases, it's really obvious (the company's earnings are out; their stock is way up; thus, they beat earnings), but in most cases journalists have to write something no matter what, so they write something plausible.

They are Fooled By Randomness :) (good book)

I was thinking the same thing. He calls it the 'narrative fallacy', saying that people invent stories after the fact to give a reason to things.

See also The Halo Effect, by Phil Rosenzweig