You're talking about two different contexts: they can make happy while with friends and family where there are social expectations, and they can also report how they honestly feel in anonymous or confidential circumstances, like surveys, studies and therapy.

The analogy I made to depression was intentional because it exhibits exactly this pattern: every depressed person consistently reports how terrible it is, and yet they often make a show of appearing happy in public.

I'm talking about the statement that "Real parents consistently make it clear how terrible having kids is."

If they "seem" happy in all my interactions, I don't see how they can be "consistently mak[ing] clear how terrible having kids is."

I also don't see how some secret only-tell-the-therapist-and-pollsters views could qualify as "consistently mak[ing] clear" their supposed negative feelings.