"For the typical palate of most people from English-speaking countries, just about all Korean food is spicy."
Uh, no its not. There are many Korean dishes that aren't spicy at all. As in, they have no spicy/heat creating element to them. The typical green Korean chili pepper (풋고추) is not hotter than a Jalapeno pepper on the Scoville scale, anyway.
To answer your questions of "Are there some Korean dishes that even some Koreans avoid for being "too spicy"?"
Yes, there are. Because not all Koreans enjoy eating spicy food. So some Koreans might avoid a dish thinking its too spicy for them, that others may think is not that spicy.
"I want to know if there are certain specific meals in Korean cuisine which generally have the reputation of being the hottest."
Sure there are some meals that some people think are very hot, but I think its pretty subjective. It could be 20 dishes. And obviously, lots of dishes can be made less spicy or more spicy so its sometimes just up to the cook.