>That's my point. Make the wrong correction in RWD car and you end up oversteering beyond 90 degrees in an unrecoverable spin. The failure modes of FWD understeer in the snow are all recoverable.

You're making one of those textbook correct but reality wrong statements that clipboard warriors love.

Sure, you can recover from under-steer but if you're already doing the wrong thing and pointing the wheel where you want the car to go you almost certainly won't.

With over-steer if you do the "natural" thing and steer the wheels toward where you want the car to point at least you have a chance. Sure many people might flub it but that's a heck of a lot better than the "no chance" you get if you react the same way to under-steer. Also, if you do over-correct the over-correction may very well not be as severe as the initial over-steer giving you a better chance to get it right the second time.

Sure, under-steer is theoretically recoverable and with over-steer you can theoretically spin or slide backwards but in reality in "on the street" situations (i.e. not what you see someone doing on an old taxiway in a training video) 99.9% of the time you'll have hit something long before either happens.

Also losing control and hitting a tree with your front crumple zone is much better than hitting the same tree side on with the driver door

That is the understated safety factor of understeer, but people prefer to think in terms of never doing mistakes instead that in terms of overall safety