Hughes served three years in prison for his involvement in a fatal car crash but Oyston insisted the decision to sign him was purely a football one.
"Of course I can understand the publicity this transfer will get, but whilst I understand, I don't necessarily agree or sympathise," he told the Blackpool Gazette.
"I take the view that this is a football decision and we make football decisions for the benefit of the club. Our job is to win matches and stay in this division, and that is very much what we are focused on.
"We have signed a player we all believe to be very good and talented, and who will definitely bring things to the squad that maybe weren't there before."