Clace, I agree with what you're saying, but I'm not sure this needed a whole thread. This is really the kind of thing you say in the moment. When someone uses one of those "What are you, 14?" lines in a thread, you jump on them then.
But generally yes, some teenagers deserve more credit than those in their age group are often given (hell, I'm technically still a teenager. I just don't feel like one anymore). However, using myself as an example, I know I've grown A LOT in just a few years. I used to get so pissed when people valued my opinion less because I was younger. But when I look back on it now, I see where they're coming from. When I hit 13, I thought I owned the world, and unfortunately, a lot of 13 year-olds do. Without even consciously trying to.
That doesn't mean age discrimination is justifiable, but there's at least a rhyme and a reason to it. Unfortauntely, that's just how it is. If you're one of the mature enough ones not to deserve it, then unfortunately it's your burden to just live with it.
Specifically on the subject of prophets though, I think they're all attacked because of their potential phoniness. That just may not be the specific aspect of them that people choose to attack. Ex: See prophet thread, get ready to flame, read thread, learn the prophet is a kid, choose to demerit him or her for it. The prophet is getting flamed for being thought to be a false prophet, even though it's his or her age that's feeling the heat. People just resort to anything they can to demean people they've deemed worthy of such treatment.
Ultimately, Demon Kirby said it best.
Generalization is a bad thing.
This post wasn't supposed to be this long. O_<