These are professionals. Pay them enough money or give them access to the ability to make money like Lee DaHye and they will come. There's nothing inherently right or wrong with anyone from any country becoming a cheerleader if the teams think they can make a profit doing so.
I only follow the cheerleaders from the USA. My favorite is Choi Hongra. Something about her. I read the comments translated into English. Sounds like many think the local girls were "Messy" and the Koreans precise. One reason maybe in the video, there were a lot less Koreans dancing. It might have been easier to have precision. Having a common uniform also may have helped.