Let's say a person is on vacation and doesn't worry about anything and doesn't read the news. And at this time, the exchange where he keeps Monero is delisting Monero. And time passes, the user visits the exchange - and what happens with his amounts on exchange that was be in Monero?
A top privacy coin like Monero held in a centralized exchange? What's the need of buying and holding it there, if I may ask? It's not as if it's some kind of altcoin that can easily be moved by demand, which they can say is in an open order that made the holder leave it in an exchange.
Let's assume someone is as dumb as to leave their XMR in an exchange and it gets delisted. The person is only left with two options: either they contact the exchange and their coins are manually sent to them, or they consider it lost forever. It's as simple as that.