How should we approach foreigners who are interested in Korean culture?

As far as I know, I have a friend who is a fun expatriate, and she said that she doesn't really like non-Koreans using Korean. Her opinion seemed to be because some 'Koreaboos' have a negative perception of consuming Korean culture with light interest. However, her Korean pronunciation is not completely natural, and she has never lived in Korea for a long time. On the contrary, I have seen many Koreans welcoming and appreciating foreigners who show genuine interest in Korea. Could it be that Koreans living abroad tend to protect their 'Korean identity' more? Is it because of the anxiety felt growing up as a minority in Korea? What do you think about this topic?