> they simply say the company was "ageist" and blame it on age discrimination.

This is a topic I'm very interested in (and as I've gotten older, my interest has only grown).

In ~20 years as a coder I've seen only a handful of overt ageist issues. I've seen plenty of ageist language and attitudes, and even more assumptions, but those are a lot harder to answer "Yeah, but would they turn down a qualified candidate for that?" about. I've known people who were both experienced and open-minded, as well as those that were experienced and closed-minded.

End result: No idea what to believe. I'm not comfortable assuming one way or the other, because either assumption is harmful if incorrect.