Measures of intelligence aren't some strict binary of "if someone does/says [xyz] they are smart and if they don't they're not", particularly if it's *just* hinging on [xyz] topic. You don't even need to dig too hard here on fedi to find plenty of grade-A specimens of "not smart racist/antisemite".

For an unrelated and tengential example, think of something like math. We wouldn't say that someone who can't do linear algebra isn't smart, because that's an entirely arbitrary metric. Conversely, we wouldn't assume someone who can do basic multiplication is a genius, because that's stuff you learn in third grade or whatever. However, if you find a first grader who independently hammered that shit out independently in his free time, he probably is smart. It's a relative measure.

All that to say, in a veritable sea of racists and antisemites, that's the norm. The expectation. Rote antisemitism/racism, more than anything else, makes you *more* average in that environment. It does not elevate you relative to your peers, etc.