[dang]

I took a look at the thread I think you're referring to, and both those comments and their upvotes are by established users with no signs of fakery that either we or our software could pick up on.

What you observed is probably a different phenomenon: early comments in a thread often start off negative, and only later do other users show up to post positively—their motivation being to balance things out. Often the positive comments to get the most upvotes in the end, but the whole process takes a while to play out. If you've ever run across a thread where the top comment says, "I can't believe how negative this thread is!" and proceeds to make a positive case with great fervor, this dynamic is probably why.