Most teenagers go through stages of liking crappy music.
I loved Nirvana/pumpkins/soundgarden 'grunge' when I was 11-13 or so, 'punk' from 13-15, industrial or whatever you call wumpscut, covenant etc from 15-16, aphex twin/squarepusher/lamb/portishead 17-19.
From then till now (24) Ive really listened to a little bit of them all and a lot of other stuff, have loved tool since I first heard Ænema in 97 or so and still listen to it a bit.
I never had MTV but i guess recovery (an abc tv show back in the 90s) was pretty influential. I still have the tape of when they talked to me in the city selling newspapers and came back to my place. :)
I don't think you can say everyone who listens to pop-punk is a tryhard following trends, many probably like many other types of music as well.
EDIT: Feel free to call any/all of those bands crap. I like/d what i like/d.