There's a lot of discussion about this here. I'd say the evidence suggests that if you're on a steep uphill, a much more rapid reduction in speed is allowed. Similarly, on a downhill, you are not allowed to decelerate that quickly.
In my personal experience, I've never once gotten hard braking from completely releasing the accelerator, even on a hill (uphill or downhill).
And I've had some extremely rapid stops, completely releasing the accelerator rapidly, on steep uphills, never got a hit. I never even worry about slowing down when I'm going uphill, or jerking my foot off the accelerator.
The reason discussed here for this difference between uphill/downhill is that the vehicle is using the accelerometer in the vehicle to measure the forces. And that would be more forgiving on an uphill than a downhill (as it should be, since the tires have to work a lot harder on a downhill for the same rate of wheel speed reduction).