Why exchange hacks keep happening
Exchanges keep part of their coins in hot wallets, connected to the internet so withdrawals are fast. That makes them a target. History is full of examples, from Mt. Gox to many smaller platforms since.
Some exchanges cover losses, some do not. Either way, customers often face paused withdrawals while it gets sorted. The easiest way to stay out of the headline is to keep long-term savings in your own wallet.