It is constructive. There are a bunch of people who are interested in self improvement, trying things, failing, and then picking themselves up and trying again.
That's rare. You don't find that in many communities. Most of the time it is just negativity and "you can't," "you shouldn't," "here are all the flaws," etc.
Hopefully this grouping of people and ideas will help all of us in some way, they do say that it is the people you surround yourself with...
I recently saw a thread on Slashdot (which I hardly ever read these days) started by someone who'd got a bit burnt out and whose skills were by his own admission out of date, asking how to get himself back into the game. It got a lot of replies saying "staying on top of the game is your job, which you are clearly terrible at: give up now" and no actual advice. Which made me realise just how (generally) positive, inspiring and helpful HN's occasional burnout threads are.
... of course, you'll find plenty of reposts from HN.
One comment: '"Permission to suck" is quite the erotic sentence :)'