the advantage is for the exchange to weed out bad people
It is trivial for a criminal to buy your leaked KYC data on the dark web for a couple of bucks and sign up to any centralized exchange using your details. KYC does not help an exchange to "weed out" criminals.
Leaking of KYC is not the disadvantage of it, that is a hacking and you could get the whole hot wallet hacked too and your money would be stolen, that's not really a default state of it.
If I keep my coins in my own wallet, then I can take security precautions against them being hacked. If I hand over my KYC details (or my coins) to a centralized exchange, then there is absolutely nothing I can do to protect them and history has shown us time after time after time that centralized exchanges have awful security and are being hacked constantly.
I believe that exchanges should always ask for KYC because it makes it that much more legal and that makes it that much better for governments to accept it as it is as well if you ask me.
So you want the government to step in and have complete control over bitcoin just as they do with fiat? Um.... no?