Criticism, behind closed doors or strictly in the company of other engineers with the correct training and experience, is not dangerous.

Criticism shared with non-engineers amounts to second-guessing and degrades the trust of the public in the profession as a whole, which has tangible negative outcomes for everyone.

Imagine if every project you'd been on had another developer bending the ear of management saying "oh, that's the wrong editor...oh, that's not the right algorithm to use..."! It'd be awful.

For mechanical and structural engineering, both much more difficult and unknowable than software, it is of the utmost importance not to foment doubt and uncertainty in people who are by definition unqualified to properly understand the criticisms and weight them.