He was a lot closer to Mansell in '91
I agree with you but from interviews I've read and listened to, Ricardo didn't like the active cars much either. As the car was doing the corner work for you (controlling the balance of the car) he never fully trusted them and just didn't like them as much. I think the brut force style of driving that Mansell used suited the car better.
The '91 car was still mainly "analogue" and based on driver feel and style and I think that's why he managed to do a good job against Mansell.
The more the cars became "digital" the less Patrese liked them. Admittedly it was towards the end of his career but it was even more evident in the all singing and dancing Benetton which had more electronics and aids than a fighter jet, lol.
Similar in a way to when we had the grooved tyres or even going over to the hybrid era, some drivers prefer a different type of car.