Numerous cases of backdoored wallets, or poorly implemented weak private keys generated from javascript, or straight up theft from deposits.

While a tiny aspect of dealing with Bitcoin is secure (key pairs) [1], actually using Bitcoin has proven to be a mess for almost the majority of users.

This is not a user friendly experience for most users.

[1] https://lbc.cryptoguru.org/about

Not the ledger, the exchanges. And then it's impossible to recover the money because the account it's gone to is anonymous.

I assume he meant people have had their coins stolen, usually from exchanges, really not much different than your bank getting robbed, although in this cause your money is gone and the exchange doesn't cover the theft.