As a non-Korean person living in Korea, I can tell you that Oli is absolutely causing harm through his antics.
First of all, as Zeus said, his ridiculous attention-seeking behavior is typical of mental illness that goes untreated because people milk him for the lolz. He is a lolcow, pure and simple. Being white and rich also makes it tacitly okay and funny, because we all love watching trainwrecks that can afford to wreck themselves over and over again. If Oli was poorer or nonwhite, I can GUARANTEE that the response to him would be exponentially nastier because he gets a privilege pass for his behavior. He’s obviously mentally ill. Milking a lolcow isn’t cool in my book, but when there’s money to milk, people won’t stop.
Second, he is a literal embodiment of a Korea fetish, which is a serious issue that needs to stop. Fetishizing anyone needs to stop. He doesn’t know shit about Korea at all except for the Koreaboo fantasyland, but that’s what he’s reduced Korea to. That’s insane and wildly disrespectful to the culture. A lot of Koreans will certainly be happy to see that outsiders are interested in Korea at all, but not in this superficial way. If he likes K-pop and some aspects of Korea, great! But he doesn’t know shit about actual Korea and can’t tell the difference.
Third, Korea already has a xenophobia problem without people like him making foreigners look even more unhinged. It’s already difficult enough to be respected as a foreigner living here without the steady stream of willfully ignorant Koreaboos coming in from abroad and acting like clowns. Literally any dumb shit a foreigner does will end up in the news as “FOREIGNER DOES_______!” “FOREIGN MAN/WOMAN IS ______!” Whatever money he spent here while traveling doesn’t compare even slightly to the amount that other foreigners contribute to Korea’s economy while still being treated like garbage (ie other Asian migrant workers in factories and farms).
TL;DR Oli London deserves to get the mental health support he CLEARLY needs instead of being brushed aside as a harmless eccentric, and he can stay the fuck away from Korea until he develops some self-awareness.