Those that keep their funds on exchange are aware of the risk that they're taking. So for those that have funds like in an exchange for example Binance's launchpool. They know that the risk is there if ever something happens to binance as there is no keys that they hold. But they choose to stay there because of the required stay for most of the tokens that they're about to earn through that feature. Otherwise, those that just uses them as a storage don't have a lot of difference on them.
Some of them aren't aware of the risk, they don't know and some of them don't care to know or learn. I use centralized exchange because in those times, where to buy Bitcoin is hard without getting scam but what I do is as soon as I buy the coins, I withdraw it immediately to my personal wallet, this way nobody will get access to my coin.
Many times, some centralized exchanges has been reported of stolen tokens and locked account that users couldn't get access to their funds, this is why you should never keep coin on centralized exchanges and if you must use it, don't keep coins on the exchange because not keys, it's never your coin.