Criticism signals that you've found something wrong with the system (which implies secret knowledge, which makes you important and insightful).
Cynicism gives the appearance of the next level up, like the exasperated person who grew tired of yelling "Wake up, sheeple!" and now simply looks for grim solace in other intelligent people who can understand his cryptic signals (which identifies them as fellow intelligent people).
It's incredibly easy to fake this, and it makes you look intelligent, so people will keep doing it because humans are evolved to seek public validation and importance (because historically, importance grants a higher opportunity to monopolize more of society's resources, giving you a survival edge to pass on your genes).
TLDR: It has everything to do with social signaling and the appearance of social importance.