If there's something wrong with open source software as a class, that thing would almost certainly have to be wrong with the AGPL as well, since it's a central example of the class of open source licenses, and, contrary to your comment, one of the most popular ones. If it's an exception to the generalization, you need to explain why.
So it isn't "slight hyperbole". It's utter incoherence.
If everyone in a classroom but one makes the same mistake, it's not incoherent to say the class screwed up.
And they half explained why AGPL is different, with the other half not being hard to infer. It's the only one that isn't donating code to huge companies, because they can't use it on their servers without sharing back.
Give a tiny bit of benefit of the doubt that they were saying something coherent. Please.
(Their other later comment says they considers AGPL to be in a different category from "open source", and even if that's wrong it actually makes the argument more coherent. They're explicitly criticizing open source licenses other than AGPL.)
So it isn't "slight hyperbole". It's utter incoherence.