But it is not only love between China and SK:
The Joint Chiefs of Staff pointed out, "Today, at 10:10 am, five airplanes of Chinese nationality were caught entering KADIZ from the west to the west, and our air force flew in an emergency."
The JCS said, "The Chinese nationality aircraft flew through JADIZ (Japan Air Defense Identification Area) and finally departed from KADIZ in the western part of KADIZ even after 1:47 pm via KADIZ."
The Chinese military aircraft entering KADIZ are known to be two H-6 strategic bombers, two J-11 fighters, and one TU-154 reconnaissance aircraft.
http://www.yonhapnews.co.kr/politics/2017/12/18/0503000000AKR20171218107452014.HTMLChina sees a potential for a hapless puppet in current S. Korean government and is try to subjugate them by constantly leaning on them. Sometimes being nice won't pay. It only invites more contempt. I doubt that Moon and his ilks learn from it, though.
They are a pack of dyed-in-the-wool pro-North/anti-American Juche left with Moon as its figurehead. They pretend they are no longer that way, but that is just for show. They never denounced N. Korean regime and have always opposed a legislation for N. Korean human right. Naturally, they would rather side with China than U.S.. But neither China nor N. Korea is cooperating to put on a nice public show they want in order to claim that they are in control of the current situation in Korean Peninsula. To Chinese and N. Koreans, they are the ones in control, and S. Korea just needs to shut up.