Commie Racialism
From Two Koreas' Top Brass Resort to Racist Mudslinging:

The North's delegation leader Maj. Gen. Kim Yong-chul started off an unfortunate thread by quipping, "Since the climate in the South is warmer, the farmers must be hard at work." His South Korean counterpart Maj. Gen. Han Min-gu of the South replied, "The population of the farming communities is actually falling, and many bachelors from such areas marry women from Mongolia, Vietnam and the Philippines."

Kim reportedly grimaced and snapped, “Our nation has always considered its pure lineage to be of great importance -- I am concerned that our singularity will disappear.” Instead of contradicting him, the South Korean delegation said such dilution of the bloodline was “but a drop of ink in the Han River,” adding this would cause no problems “if we all live together." But this failed to mollify the North Korean. "Since time immemorial, our nation has been a land of abundant beauty. Not even one drop of ink must be allowed to fall into the Han River,” Kim thundered.

Of course, Maj. Gen. Kim's talk of "pure lineage" is as nonsensical as every Korean tracing his ancestry to nobles. Maj. Gen. Han's "drop of ink" is equally nonsensical; a full third of rural Korean men take foreign brides.