Anti-American sentiment in Korea was extremely high during the Bush W. Era because of several incidents.

I don't really feel like explaining them, here is a link to an article about a song here from that time: https://en.wikipedia.org/wiki/Fucking_USA

Mr. W.Bush (rightwing) visited Korea with a painting he made of Mr. Roh (leftwing) and brought it to his memorial.

In my opinion, by then no one really disliked him anymore because he wasn't really the cause for much that happened here, he was just the guy in charge. Also, the current president of America is really trying to fix some things about Korea.