I think it's also important to distinguish "negative" from "critical thinking".

While we can probably mostly agree that sniping (especially personal attacks) are rotten, I suspect useful insights, that are critical in nature, often get thrown in with the dirty laundry, and labelled as "negative". "Awesome site dude!! SO happy for you :) :)" and a whole bunch of potentially fake, shiny superlatives can also become a turnoff.

Quite likely this is a minority viewpoint.