You can replace all this wall of text for:
Remove your money from exchanges and put them in a wallet where you hold your private keys.
Nothing is ever 100% safe, even with your private keys hidden someone can physically attack you and torture you until you give them up. In some cases people feel safer with a 3rd party. Not everyone wants to be their own bank.
I agree with you about that we can't expect something it could possibly happen even if you think you're money is safe but it's totally not. The risk is always there, people who have bad intentions is also there so we should not be inhabited.