Lots and lots of people here read TechCrunch. It's still essentially the paper of record for the startup scene. Consequently, when major interesting news breaks, several different people see it on TechCrunch first and all submit the article at about the same time. The duplicate submissions count as upvotes, and just 5-10 of these immediately after an article breaks is enough to get a submission near the top for a short period of time, during which it's the first link on the story people coming to the HN frontpage see, so it gains momentum.
Honestly, I don't think TC is as bad as you characterize it, especially when it comes to breaking news (as opposed to high-level commentary). They've done a good job at breaking several big stories in the past year, even though I disagree with a lot of the more opinion-type pieces.
