WRONG. There are some Gould Mozart interpretations that actually stand up to serious scrutiny (his recordings of the C Minor Concerto, FIRST recording of K330).
And what's this rubbish about him hating Bach?
He was actually quoted as saying he didn't like Mozart very much. Of course he may have said that just to be mischievous.
As for Bach -- you only have to listen to his recordings.
I don't actually think he hated Bach -- it's not that simple. Gould was a ferocious technician with a highly original musical intelligence. Bach was the only composer who could keep his attention for very long. Perhaps Bach was some sort of father figure to him, to be alternately ridiculed and worshipped.
Take the second recording of the Goldberg's. It's about 1/3 Romantic excess, 1/3 sublime epiphanies, and 1/3 plink plink bang bang.
Unfortunately that recording has been very influential, and all the amateur pianists now think that's what the piece is supposed to sound like. Check out Youtube if you don't believe me.