I've always exercised a lot of restraint when it comes to criticising teen writing because, to be honest, most of us write very poorly when we're young, and also I find it's hard to really push people in a constructive direction unless you actually have an established rapport with someone. I think people also become more able to process criticism as they get older, so there's a reticence about how a teenager will process a critique.
I think most other people operate on a similar sort of understanding. It's pretty hard to critique a 15 year old's wikibox timeline without it ultimately all coming down to 'you just have another ten or fifteen years of developing before this is going to be of any worth or merit'. And that's basically as good as saying 'Stop writing'. I find it hard not to believe there's an inherent obnoxiousness about criticism from me to them.
NDCR was certainly a deeply unlikeable phenomenon for a whole host of reasons, but I held back on it and let posters who were closer to the age of the people involved with it deal with it directly, and they did in a very effective way.