I think the author is trying to lend support to people who feel excluded from the field due to a lack of credentials - great! You can, in fact, materially contribute and succeed without a PhD. Machine learning is a pretty big tent.
Claiming that a profession is meritocratic, though, strikes me as a harmful framing. From my vantage I don't see a) what an objective notion of merit would be and b) that all people who have the capability to contribute is strictly equal to the number of good jobs that are currently available.
I can definitely see when someone is already doing something useful well, but not if they might do that later or if the notion of useful will change.