That’s an interesting point there, but have you considered that even with a mechanical link and current safety features, it can still override you? I unfortunately almost drove into someone at very low speeds in a dark rainy parking lot, but the cars safety systems overrode me thankfully. I don’t think they would have been injured it was so slow, but just to show that nowadays with cars you don’t always have full control. In that case it was the brakes not steering, but modern cars can and will prevent you from changing lanes into someone in your blind spot for example.
I'll be honest with you: all but one of the half-dozen (which is too many, BTW) cars I own have manual transmissions, and half of them don't even have ABS, let alone any other fancy electronic nannies. I mention that to help explain the extent to which I am fundamentally Not On Board with anything that interferes with my manual control of the car. (I'm also a Linux user and a DIYer, which are some more clues to how much of a control freak I am: I expect my property to be exactly the way I want it to be and do exactly what I want it to do, and nothing else.)
Putting torque on the wheel while in these semi self driving modes disables the self driving features, but that’s software that disables it when you take over. What if that software failed and you were now fighting the self driving car also trying to steer and as you tried to steer it put equal power against you thinking the steering was rough?
Don't get me wrong: I wouldn't mind having radar cruise with lane-keeping for long trips on the freeway, but only if such a system were fail-safe enough that even if it were stuck on, yanking on the wheel hard enough would get the car to turn. I would absolutely insist on the maximum torque the self-driving system could apply being much less than the strength of the human driver. I don't know if that's the case in late-model vehicles or not, but if it isn't, I would consider those vehicles to have an unsafe design.