The amount of "bad" games correlates positively with the possibilities for teenagers to give their 'well-founded' opinion to a mass-public. It also correlates positively with the amount of routes to free content through piracy.

This meaning,

The idea that a specific game is bad is fueled by a vast majority of young people giving un-founded criticism. Add this with the fact that negative aspects of something are more likely to be talked about and you have a situation where a bunch of youngsters are cracking down a game based on hardly anything.

Also, with piracy becoming mainstream it's a lot easier to have free content. Research has shown you're more likely to see something as good/positive the more you had to do to reach the goal. Having to work to be able to pay for a game you bought in the store equals effort (work, pay, go to store, etc...). Downloading something from the internet is almost no effort.

Most of the games are good enough to enjoy yourself for a couple of hours.