For me, it's okay to pay withdrawal fees if they are very low and near to real life cases, like, if the fee of average Bitcoin transaction is $0.50 and casino charges me that, I'm okay with that. If the Litecoin withdrawal fee is $0.01 and casino charges me $0.50, that's not okay for me. I prefer fair fees for every kind of cryptocurrency.
Casinos actually don't charge you withdrawal fees. Rather, they call it withdrawal processing fees. I believe withdrawal works like exchange; they make multiple withdrawals on the same transaction. Means it will cost more or less. But often they fixed the withdrawal fees from users. This is their business as well, like exchanges. They know very well when a user makes a deposit, they will withdraw as well. So they earn even from your withdrawal. I don't think there are any casinos that don't charge withdrawal fees. Fair fees won't be expected from the casino, which means network fees.