This really shouldn’t be surprising to anyone, the only thing surprising is how open this South Korean diplomat was about how pro-American diplomats have been marginalized in the Moon administration:

New Korean Ambassador to Vietnam Kim Do-hyun

The Foreign Ministry Tuesday admonished the new ambassador to Vietnam, Kim Do-hyun, for his critical remarks about the United States during an interview with a vernacular Korean paper.

The remarks in question are as follows: “The reason why the inter-Korean summit was successful is because pro-United States diplomats were not put in charge. … a majority of Korean diplomats have thought they could get promoted if they were close to Americans and if not, they would have no future.”

A ministry spokesman said, “Ambassador Kim went to his post several days ago. Since he will have many chances to have interviews with media, we have internally taken necessary steps.”

He said that he didn’t reveal what steps were taken but didn’t object when asked whether it was tantamount to a “verbal warning.”  [Korea Times]

You can read more at the link, but I infer from Kim’s remarks that the Moon administration has marginalized diplomats considered pro-US and are only using North Korean sympathizers to interact with the Kim regime.  This is not surprising considering the Moon administration has many left wing North Korean sympathizers.  For example President Moon’s Chief of Staff, Im Jeong-seok is a former supporter of North Korea’s juche philosophy.