There was a time back in the 90's that if you had a Kia, Hyundai, or Daewoo, you'd have a hard time trading it in. Dealers didn't want them, not here in Maine anyhow. The build quality wasn't really there at the time, and dealers that didn't sell and service new Korean cars didn't want them. The Korean auto industry has come lightyears since then. I suppose you could compare those cars to the Korean tractors from the same era, but much like the auto industry, you can't really compare them to the machines produced today.
I presume any dealer claiming they won't take a modern Korean tractor in trade has some underlying issues, and I don't want to deal with that. A proper dealer would at least offer you a low ball trade-in, or suggest you sell your machine outright 'to get more for it.' Why would you just outright alienate a portion of your potential customer base from the start?
Idiots, I suppose.