Please, it takes no balls to diss(1) a newbie(2) over the anonymity of the internet(3).
1. "It's crap", and "you clearly put no effort into this", while nobody wants to hear them, are not insults. Effort shows, even if it's misdirected effort. Furthermore, the comment is directed at the art, not the artist. People who don't know the difference should learn it early, and people who do know the difference and get offended anyway are way out of line.
2. Everyone, not just newbies, halfasses or makes crappy art at various points, and not calling somebody on it just reinforces their bad habits. Harshness, if nothing else, causes someone to stop, rewind, and re-evaluate their art.
3. In my experience live critiques are way more harsh. Anonymity is a non-factor.
I really don't want to drag this thread out, so I'll just leave it at that and invite anyone who wants to discuss this further to do so via pm