I would argue that gossip and backstabbing are intrinsic parts of our societal fabric. Whether that's good or not is another conversation, but that pathos is the undercurrent of modern society. Which is to say, as a species, most of us never socially evolve beyond 7th grade politics, whether we want to admit it or not.
The good news is, even though I firmly believe most people are insecure assholes (most definitely including myself in that category), I also believe that most of us will choose kindness and empathy when given the opportunity. And you see that on Secret too. For every delicious thread I see about gossip or bitching about a startup or media company, I equally see posts or comments that represent the better parts or humanity - like support, encouragement and validation.
If anything, I'd argue that the anonymous nature or Secret makes it easier for people to be cruel and pile-on, but it just as equally makes it easier for those that disagree to defend against the pile-on and interject an alternate perspective. If I'm gossiping with friends or associates and people start talking smack about someone I kind of like or am ambivalent about, I might not interject, even if I want to. In my lowest moments, I might even find myself joining in. But if I'm anonymous, there is nothing holding me back from dissenting because the social repercussions of having a different opinion are non-existent.
In other news, I'm clearly overthinking and over analyzing Secret.