Wow, not the kind of engineering room I'd want to be in. You have to be able to make claims that the other party does not have a complete picture of the situation, and an external critic is indeed going to be vulnerable to the same criticism.

Maybe you would have a point if it were a Linus-style "only a fucking idiot would" rant. But responding to a sincere attempt to defend a design decision as if it were an insult is some prima donna behavior.