Sechel, lots of gedolim write things that can be misunderstood and require a mesorah from their talmidim to understand. You’d be the first to say that god-in-a-body needs to be understood, supposedly, by people who understand it.
Rav Belsky was close to rav moshe and got shimush from him. I trust his understanding of rav moshe, and it’s the same reason why rav Moshe grew long payos…it was with an honest appraisal of his ability as a posek and a belief that American jewry needed a competent posek, amid a lot of rabbis who were ruining yiddishkeit or who were quasi conservative. That’s emes; truth is nore than uncle moishy songs about never telling a lie. Same way chazal say that we need to praise even an ugly kallah; that’s emes to Hashem.