Your keys your Bitcoin so if you put your Bitcoins on exchanges then they have your keys and therefore they have full control of your coins. It is too risky as well to put your Bitcoin on exchanges as it is prone to hacks and other data breaches.
Exactly and I would like to think not only hacks too, as since it's an centralized entity, the owner can just come up with blatant excuses like the system being breach or hacked just like the way sam bankman fried tried to pull off an exist scheme because thats what I called that idea of his. If am to advice anyone about centralized exchange I would probably just say we should just keep a portion of the Bitcoin we actually want to sell because storing your Bitcoin in an centralized exchange is risky because you don't know what the next story might be concerning your coins in there.