I couldn't agree more. While it may not be a "show hn" project, the developer may still be a member of the hn community. If one is going to criticise the project, they should at least do so constructively so they can improve it. I don't think any of us would really want snarky remarks as the feedback to something we poured our free time in and shared with the community to garner feedback.

Treat other developers in the same way we would want to be treated if in a similar position :)