Opposite to what? When you deposit into an exchange you are not given fiat value into your exchange balance, but you are given only RIGHTS to trade onto their exchange with their offered value of your deposited asset.
You have to consider that, like crypto hot wallets, an exchange also have "fiat hot wallets" to address user fiat conversion requests on daily basis.
This means that part of the crypto coins must have been converted in to FIAT before the takedown. To allow users to withdraw if requested.
Exchanges usually convert a percentage of users' coins daily to feed FIAT hot and cold wallets.
Therefore, since the "FIAT hot and cold wallet" are presumably lost, a complete refund of all the assets is quite difficult, especially on the FIAT side.
But hey, I hope I'm wrong
