Wait, what? I did respond, illustrating how ignorant your comment was of the region, and how it is pretty offensive, and why it's comments like yours that made the problem we have. But hey, you aren't offended by lumping them all together, so it's OK. SMH. How about you actually educate yourself on the history of Korea, especially those times when the entire Korean culture was attempted to be eradicated (more than once), before saying that there's no issue with just lumping them all in together as generic Asian.
I can't speak for all Koreans, naturally, but the thousands of them I've spoken with over the years while living there, get pretty pissed off at any hint of lumping them in with generic Asians or Japanese (especially). There is still, to this day, a lot of animosity between Korea and Japan. Having their unique culture and history constantly pushed to the side or ignored is a big deal, and they have every right to be sensitive about it since more than once other cultures have tried to erase them from history.