I have to say the article didn't seem to say much of anything. It wasn't a stereotype so much as incoherent. I actually do think there is a case to be made that many modern cultural Jews straddle the fence between liberal culture and conservative family values, but that's not particularly on topic with what the article is after.
I do find this bit interesting, though:
Unfortunately for the Jewish community, a great deal of religious observance has been replaced with the worship of social-justice movements and a belief that tikkun olam (translated as “repairing the world”) is what Judaism now requires of us.
Tikkun olam is straight out of kabbalah, and although strictly speaking rabbinic Judaism is supposedly based on esoteric kabbalistic teaching, the Judaism taught in synagogues and practiced by most Jews does not actually partake of this view or even mention the kabbalistic view of the broken universe at all. It is notoriously the realm of the Hasidim where the good deeds and fixing of the world to bring the messiah is invoked, which makes is odd the article should mention this as if it's the cornerstone of the average Jewish person's life. Most have probably never heard of it, or at least if they have they don't really know what it's about. By itself this might just mean that the author of the article is ignorant of this, and also of the fact that 'social justice' as such has pretty much zero to do with fixing the world in the sense Hasidic Jews mean it. They are not about doing good deeds in the generic sense; they have a very specific list of things that need to be done to put money in the messiah piggy bank.
When reading Al's article I was reminded of a strange pattern of Obama referring to tikkun olam and how it is part of his life. He's said it at various Jewish-themed events over the years; here's a video of some of them:
https://www.youtube.com/watch?v=8bAevuoRj34I was kind of nonplussed when I first heard him say this since it made me wonder whether he's speaking on a very general level just to say he believes in kindness and good deeds, or whether it might mean he's into kabbalah specifically as at present many celebrities are. If so that would be kind of interesting since that absolutely would mean he cannot be a Christian or Muslim since the kabbalist metaphysics is directly contradictory to both of those systems and they are incompatible.
Where this gets interesting and veers even wider than the article's thesis is that kabbalistic theology is strictly realist (i.e. moral realism) and relies on an absolute and clearly defined structure to the universe, which is more or less the antithesis of social justice insofar as social justice is the revaluation of values and the evolution of what we cared about previously. Moral relativism cannot coexist with kabbalah, making it all the more strange the article should mention tikkun olam in the same sentence as social justice activists.