"If you stand up and announce a new idea, hundreds if not thousands of armchair quarterbacks will tell you why your idea is wrong / how they could do it better / why they are smarter than you"

or

"Good job thinking critically about an issue that literally millions of people have taken for granted for years and trying to come up with out-of-the-box solutions, backed by actual quantitative research."?

Personally, I want to communicate the second. Will he have to learn that solving problems involves creating ideas and then iterating on those ideas, sometimes tearing the original idea to shreds in the process? Yes. Will he need to learn to divorce himself from his work and not feel that criticism of his work devalues him as a person? Yes.

But some (not all) of the HN comments, while critical, do not feel exceptionally constructive. Too often, when some unique or innovative new idea is touted, smart people rush to explain why it won't work or why it's not actually that great an idea or why it's solving the wrong problem in the first place. But none of these people are actually helping to solve the problem. It is important for us to have this talk about fixing the frankly toxic attitude that seems to pervade this space sometimes. And it's important not to hide behind the shield of "constructive criticism" when the criticism is less constructive and more just petty.