My idea of intelligence is different than mainstream society's. Like knowing all the answers to jeopardy questions doesnt make someone smart. Take the smartest person you know and imagine how smart theyd be if they never had any schooling.
The mind is like a muscle, the more its used the stronger it gets. Deaf people in the past werent given the opportunity to exercise their minds so maybe theirs was a little weak. But they never had a chance to make it stronger.
