I wonder why it's discouraged? I think it undermines antisemitism rather than otherwise. As it's a benign explanation for jewish overrepresentation in cognitively demanding endeavours.
First because it validates the hypothesis that there are significant differences in intelligence between ethnicities (i.e. if Ashkenazis are genetically smarter, perhaps the lower avg IQ in blacks is at least partly genetic).
And second, it can cause some people to perceive Ash. as "others", enemies and give rise to various conspiracy theories.
I'll grant you the first point. But what sort of conspiracy theory? It elegantly explains overrepresentation without any coordination. Once you account for the Ashkenazis much higher IQ, there isn't anything for a conspiracy to explain.
And second, it can cause some people to perceive Ash. as "others", enemies and give rise to various conspiracy theories.