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.
Those who don't want to be their own bank, are sure to be the first to mention that the exchange or third-party wallet is scam and all that attempt to blame someone for an error of his own.
Nothing is better than having control over your funds, even if it is not 100% secure. I transfer to the exchange only when I want to trade and I withdraw quickly...