I agree, if you went to a non specific website that was just about Korea in general, then most folks might not know about dog breeder info let alone Yorkies in particular. It is true that folks treat little dogs like accessories ,but it was not fair for these folks you didn't know to stereo type someone they didn't know. They just took a cheap shot at your expense.
So if you are serious about getting a Yorky in Korea, you should ask the question at the AKC or if you are in Canada, the CKC website and ask about talking to someone who would know about a breeder in Korea. They might even be able to tell you about rules and regulations in that country that are dog specific that you might not know about and yet need to know. If you are able to get a hold of a dog breeder in your country who does international showing, they might be able to help you also. They might know someone who knows someone
Sadly I am thinking in a stereo type way and wondering if they still eat dogs there?? If there are Yorkies there, most folk who have them would be not your stereotypical working Korean and they may have bought one from outside the country themselves.
I hope you intend to bring the dog back with you when you come back home and you will need to know information about brining a dog back into your country and how long they have to stay in quarentine and where that will take place and how much they charge for that too, plus being checked by the government vets and tests and all that stuff
That all being said, it may still be very hard to do what you intend to do. I wish you lots of luck in your indeavor! Think this through and be able to answer some hard questions if you are able to get hold of anyone to help you with purchasing a dog in Korea