Sure, but it's possible to be negative about something without being rude or mean about it. I think one of the great things about YC.news is that everyone here is a 'builder/creator' in some way, and that makes us understand the work that goes into even unsuccessful things, and perhaps less likely to simply trash them.

I think it's also much easier to zing off a facile negative comment. Forcing yourself to write something positive (or at least non-negative) helps me focus on writing something truly insightful.