Let me guess, was this gentleman also selling tow dollies? If your owner's manual says the Fusion can be towed 4 down, I'd go by that. Most cars have hydraulic power steering, it's actually autos with electric steering that have had issues and need to energize the electric steering to keep them from not tracking properly in turns. The issue of the door damage is complete nonsense, what's going to damage your doors if towing 4 down? You can also check
this source if your vehicle is listed as towable.
The only tow dollies that damage cars is because the car might have such a low clearance in the front air dam that it drags in the steep ramps. Solution: use blocks to reduce the ramp angle and most can then load and unload without issue.