To a pilot, "roll damping" is the resistance of the aircraft to roll. If you neutralize the ailerons, the airplane stops rolling. That's as it should be. You'll still need to use aileron to roll out of any bank, but a well-damped aircraft will stop rolling as soon as the input (aileron, gust, etc) is removed.

I don't think I've ever flown a model that didn't stop rolling when you neutralized the controls. You had to roll out of a bank, but you didn't need opposite control to stop a roll.