Why do Chinese people HATE Koreans?

I've noticed recently online that vast number of chinese people accuse koreans of cultural plagiarism and insult them in various ways on the internet. Also, I've seen that south korea is the most hated country in china. Many say that it was after wc2002. But why would they so vehemently hate Koreans? I'd like to hear from someone who is Chinese.

I havnt contacted with korean ever, I dont dislike korean, but I often hear of the complaints around ppl that some of them are very arrogant, especially some korean man, sometimes they are not very gentle. 

As to insult on internet, I think some are too extreme indeed. There IS a kind of ppl, they concentrate on attacking someone on the internet. Who is the target is not the point to them, attacking is what they like. I dont think they would insult somebody, if they met a korean on the streets, even though they use extreme words on the internet. They are called "fenqin" in china, I really dont understand why they like do it. 

I think there are ppl dont like korean indeed, just dislike no more no less, and there are lots of ppl who are korean fans as well, but I think most of chinese are intervenient.

the reasons for the hate is so complex. and its really hard to explain.

but a major reason is that korean netizens flame and bash Chinese/China on the internet. also they have allegedly claimed that Confucious was Korean, Great Wall built by Koreans etc.

recently however, since Koreans love Turkey due to Turkish UN troops helping them in WWII, they even believe that Turkish people and themselves are closely related. They claim this by saying that they are the same 'Altaic' people. 

Korean attitude. This is what you get when a poor country suddenly turns 'developed' the people become conceited and supercillious, due to the success of Samsung, LG, Hyundai and other Korean companies. This happened in Japan but the arrogance in Japan has died down in recent years.

However - the conceited attitude has begun to erupt in China - since their country is developing fast. In the West - the countries there are already 'developed' and the people are not as arrogant, because they are 'used to' it. 

Koreans also deny their plastic surgeries. Ive seen streets full of plastic surgery clinics in South Korea and yet koreans STILL deny it. Also, regular Koreans do not look like those celebrities you see in K-Dramas, so dont get your hopes up.

On the otherhand - ive noticed that overseas Chinese love Koreans, because of the k-pop, dramas, culture etc.having said that, many of impartial to them because they have cliques of koreans and refuse to interact with non-koreans, many of them are annoying (loud, pestering OR introverted and malicious.

Furthermore, Chinese COULD be jealous of Korean successes in football - but who knows.

The Korean and Chinese races have been enemies since their nations' founding. But in this world, the Chinese and North Koreans are allies. The Chinese hates the South Koreans because they think that they stole their identity. Some also hates the S. Koreans because of the competition on their economy, technology, looks, fame, and just everything that they other people love about them. I think this is what could possibly go wrong when two self-centered nations fight.