Was it?
When things were transparent, there were no reason to upvote interesting trollish comments.
Now they get blindly up-voted for being interesting. For example, consider this article:
https://news.ycombinator.com/item?id=7436401
About 5 facebook engineers are answering questions. They are of course buried by a meta discussion about whether facebook should use PHP at all.
Since the change, I have written a few 50+ karma comments, and all were trolls. The change makes me like my own comments less. Getting a "high score" just requires posting something popular and mildly offensive, where as before, people could weigh, "what conversation is most important".