It is irrelevant and very disturbing for the discussion. So it may not be exactly ageism, but it is definitely inappropriate.

You're right. That was a mistake on my part, I'll take it into consideration for the future.

I've seen it at about the same rate in old and young. Though older people seem less likely to recognize and correct their error.

But that's from personal observation, and I haven't made a point of recording my findings for analysis. I suspect you haven't either.

I'm not sure why you consider it hubris for me not to trust the competence of other developers without evidence.