[repolfx]

But the research project exists to inform future changes in their hiring practices.

It's quite likely Automattic already tries to discriminate in hiring because they mention their "strong focus on metrics" along with their amusing puzzlement that merely demanding more women and trans people be hired didn't automatically make it so. They certainly want discriminatory outcomes.

That said I agree with what you write. I'm not sure explicit age discrimination is common though. It may appear to be happening but is often other things, nobody is actually deciding they don't want older people. Age discrimination against young people, that's common (e.g. young people not being allowed to be CEOs, like Larry Page). Not necessarily bad but common. Gender discrimination against men I've seen a bunch of times, and it's explicit. People say "we won't hire men".