Reddit is not different with respect to this. HN, mostly, so far, but it does consider certain things more or less off topic, so it's not trying to be a general platform as such.

Sure is. I doubt there s anyone who got depressed because their reddit karma was low. Posting an instagram selfie, however, and getting no likes -- that's tough.

"Social media" is a misnomer, in reality it's skinner boxes for humans

Reddit is better because people are more anonymous and don't have to mix their real life with their online life.