From a (Korean) poster on Reddit.
DropItLikeItsHotBear•Mar 13, 2017
"DVDs" and "three for a fiver" are comments based on stereotypes. "You eat dogs in your own country" is a comment based on fact. One is intended to offend, the other is not. One minimizes the target to a stereotype, the other does not. It's probably not something Koreans like to broadcast - that people in their B country eat dog - but it's hardly the same as saying you must sell DVDs because you're Asian. I'm Korean, and I originally cringed when hearing the Park chant, but I'm not quite sure that it's racist. It isn't politically correct, that's for sure, but I'm not sure it comes from a belief that white people are superior to Asians (which would make it racist).
Personally, I don't like the chant. Pointing out that Koreans eat dog may be factual, but many hearing that would disagree with it, and hence make a judgement that it is wrong. It's not difficult to see how this may offend many Koreans (both dog eating and non dog eating) even if it doesn't offend the Korean poster that I quoted above, although it clearly embarrassed him.