Same reason the locals never shot at the Koreans in Vietnam. Koreans tend not to like being shot at. Americans never minded being shot and killed, but Koreans tended to react with massive force if attacked. The Viet Cong learned early to wait for the Americans.
bttt
" Koreans tended to react with massive force if attacked. The Viet Cong learned early to wait for the Americans."
The British navy could learn some from the Koreans too.
I worked with the Tiger Division near Quin Nhon for a short period. I know how they can be.