Thoughts are simple. OKEx Korea know everyone on their exchange, since they KYCed themself. So they know who deposited every coin on the exchange as who withdraw coins from that exchange. That is what FATF policy is all about. In FATF policy there is no reason for delisting any coin. There are just reasons for them to focus more in KYCing their customers.
It seems true but why okex has said like this
In its notice, OKEX Korea said it will delist cryptocurrencies that violate laws or regulations [and] policies of government agencies and major agencies.
Specifically, in this case, it cited the travel rule recommendation to national regulators from the Financial Action Task Force (FATF) as the reason for pulling the five coins.
https://www.coindesk.com/okex-korea-drops-5-privacy-coins-citing-fatf-rulesBut this will be only implemented in the okex's Korea based exchange but another platform still remains the same to allow the trade for these privacy coins.
I dont understand what is unclear? There is nothing in FATF policy that prevent them to have Monero listed. Nothing. FATF policy demand they know who they sell coins or get coins from. If they do KYC then they do know. Why they posted that is mystery to me. I have no ideas. They should tell the truth what is teh reason.
My speculation is that since tehre was a lot of hacks in South Korea. A lot exchanges lost founds in last years and since they cant trace those taht was witdhrawn in Monero they did this. Instead to raise security to prevent hacks or internal stealings they pulled most simple thing that will not solve anything on the long term. It will only escalate problems since transparent ledger coins are easier targets then coins that have opaque ledger and hackers dont even know who holds them.