Why would they be paying to move it at all though when the house they are buying already has perfectly good, and often better, appliances than they would be moving anyway.

Dude - consider mainstream buying options like say, Costco, Home Depot, Lowes, etc. There are apartment sized refrigerators going for nearly $1000. Can you find a super low end model for under $1K? Sure - but that's not what the majority of people are putting into their homes for a family unit of 2+ people. Can I throw a washer and dryer into the back of my truck? Sure - but that's not what people are going to do if they are moving outside their immediate vicinity. At minimum they are backing up the U-Haul, at the high end they are bringing in movers.

sounds like you agree with me, the idea that it's cheaper to buy a new refrigerator vs moving it is ridiculous.

People will rationalize all sorts of poor decisions.