You know, it doesn't bother me, and I am a fan of porn. In fact, a number of my titles are from the Barely Legal series. I don't like braces as much, but that's because I don't find braces attractive, but I do find the body type very attractive.
I know that the girls are of age, and I can appreciate what the producers are marketing towards. There is a niche for everyone, and this series is really catered towards people who find the high school girl fantasy attractive, and great for couples who integrate that kind of role-play in their sex lives, myself included. For me, its not much different than the school girl costumes that are all over the place, and commonly accepted.
To each his own, but I view the barely legal genre as a healthy source for people inclined to that fantasy. I see consenting adults producing entertainment for their customers. Period. I don't think its fair to make people feel like scum because they are entertained by something perfectly legal, only because it bothers you.
If someone is healthy enough to realize the difference between watching "fantasy" porn and actually going out and participating in illegal activities, they don't need to be told they are horrible, perverted people. They are acting out a healthy drive in a healthy way. As someone pointed out, it is biologically normal to be attracted to 14-18 year old girls. It wasn't strange to be attracted to them in high school, at a time when it is normal to develop sexual tastes and attractions, so why is it abnormal to maintain that attraction after you turn 18?
My general opinion: If you aren't interested in it, don't watch it. If you are uncomfortable with the content, then find people seeking illegal snuff films with ACTUAL underage content to condescend towards. Leave innocent people enjoying legal entertainment alone.