I blame myself for not withdrawing my funds ...
Those were not your funds. Not your keys = not your funds. Those were
IOUs which you've now lost. Anyone who is using an exchange as an wallet has nobody else to blame but themselves. Cryptopia was a horrible exchange to begin with.
Indeed it is, and no one except the account holder is responsible. Of course, Cryptopia it's a horrible exchange, but using such platforms is always risky (Binance, Bittrex etc). For this reason, I paid attention to services without registration, which I do not actually transfer my funds to. I once used Shapeshift, but they also entered an account, and now I use Changenow as one of the ways to instantly exchange my coins.