When the game draws a hand, it checks if there is enough funds in the prize pool to cover the win, if there isnt it will make you lose.
Just quoting this line, since it's the most important.
With this casino, your loss may be inevitable if there isn't enough funds in the prize pool. Which seems like an appalling way to run things. If there's not enough money to pay out a certain bet, why not prevent the user from making the bet in the first place? (Which is what most other sites do by setting a 'max profit', which basically sets the maximum the casino is willing/able to pay out)
Is it also appalling that the casino paid out sufficient winnings to players to create this 'negatively-balanced' prize pool?
As I stated previously, I don't run the casino so don't know enough about it, but IMO if this is how it works, it means somebody else won and walked away with more than they started with. Such is the nature of gambling.