Probably the schools decide by economics. Some prat digs a prop in the ground and it costs an engine and prop. So, they "think" a nosewheel will stop that?
Then once you get a couple of instructors who have never flown a tailwheel and they breed like rabbits.
I could not agree more. "Land-O-Matic" should have been restricted to "big" planes, and pilots who already know how to fly! But, the flood gates opened, and here we are.
I learned in 150s in the '70's. When I asked for training in the sole Citabria at that club, the instruction was not competent, and I was left rather fearful of taildraggers for some time. It was a wise fellow with a Tiger Moth (which did not have a tailwheel) who taught me better.