I've started tuning out the negativity in comments. I look for the constructive criticism or relevant links.
There's a lot of unnecessary trolling, which I try to tune out as well. However there are some genuinely great debates that happen in the comments .. often better reads than the original content.
Compared to most websites HN still has an extremely small amount of trolling and negativity. The community does a good job of policing it on their own for the most part.
The comments I like the most focus on how to better build and reach more customers.
I like some of the e-mails I get from HN readers.
I think the idea of the post isn't to tune out the negativity, but to thrive on it. If all the feedback is positive, you get a couple pats on the back and are forgotten. If you anger and thrill people in equal enough proportions, you have a discussion.