@tamtararam I think it's understood in this context that "professional" means "trained in design", and it's perfectly ok to say your app will follow the vision of a trained team. I'm a big defender of design as a discipline and that the expertise of designers is worthy of respect.
where it goes wrong here is the notion that education in design means you're not going to even *hear* from the users. this is kinda against everything design even *is*. it's a bit like saying "he's a trained doctor so shut up, he doesn't want to hear about your symptoms".
notice that the professional designers here weren't even asked whether they agree with the attitude; the programmer simply weaponised the fact that they *exist* to shut out the user out of hand.