[delusional]

I find this pretty easy to deal with. You just don't engage with that question. Make it clear to the people you are discussion it with what kind of things you want input on (architecture, design, product market fit), and make it very clear when you consider their input out of that scope. People will very quickly learn what sort of comments you care about.

This form on "collective design" usually uses a confrontational form of rhetoric, but the exercise is very much collaborative.