The difference in our reasoning is this. First, I have never heard a recommendation from a manufacturer, tire distributor, car forum that did not recommend equal diameter and tread wear on the same axle with the same rolling diameter. For one thing, for differences greater then 2/32 inch, the rolling circumference is now sufficient for pulling forces from one side to another to work, regardless of the safety aspect.
Second, and very conservatively, though the differential gears do work every time you turn a corner, for most people, well over 90% of the total mileage driven is nearly straight or very gradual with minor Imperceptive corrections with the differential gears working little if at all on cars set up well and as recommended. Any one with a locking part time truck 4wd understands under what conditions they can drive it engaged and gets that because that is when a center differential would have to work. With rolling diameters are substantially different because of wear greater ( then 3/32 inch recommended by Tire Rack on the same differential axle) , these gears which worked very little are now in constant motion and working, at least 90% more time wise then if the tires matched and the car set up as recommended. The only time they wouldn’t, would be when the turn matched the difference in rolling diameter influence. Obviously everything affects how they work, but you are adding a substantial amount of wear with that small difference alone.
It is the EXACT same reason why most AWD manufacturers recommend similar wear on all 4 wheels. If you are not keeping the car much longer, perhaps it is of no concern. But if you do, it definite becomes a long term wear item that is very expensive to fix. You’ll know when someone isn’t concerned. The differential in time will start talking.