Mostly because it's not productive. Ideas, especially early ones, are malleable and changing. Saying it "Sucks" is like building a brick wall. Instead you want

Mostly because it's not productive. Ideas, especially early ones, are malleable and changing. Saying it "Sucks" is like building a brick wall. Instead you want to ask something that illuminates the way so the idea improves. That being said, first time entrepreneurs benefit most from this approach while people more experienced can cut to the chase. It's all about trying to be helpful.