The lesson learned is that you should only have that much coins stored on an exchange you need for trades and IMMEDIATLY withdraw them as soon as you finished your trades. Exchanges may shut down from one day to another, happened to a lot of exchanges in the crypto space already.
Yes I agree with you.
Exchanges should be used for trading otherwise there should be no coins left on exchanges.
Peoples have been warn on several occasions not to keep huge funds or coins they cant afford to loose on an exchange site but I guess if we keep on saying this till next year some people still wont listen.
Aside that, I believe the exchange in subject team are not competent cause this will be the second time this year which the exchange was shut down while users loose their fund.