But what if they don't WANT to be an author as an occupation? And the tough love thing can work, but there's a difference between giving feedback when its asked for and giving feedback because you can. Like, I could go onto any website and say "such-and-such is terrible/awesome", but that doesn't mean its appropriate. I understand that you don't have any problems with them. I commend you on saying the truth, but sometimes you just need to hold it in. Sometimes it isn't worth hurt feelings, ok? Especially since certain people (like me!) can only depend on writing or whatever, and a single comment can ruin their confidence, which may ruin their Passion or confidence in that one thing.
But, that's my opinion.
Author's response
i respect you completely and utterly for that.