Gambling making a consistent bet in gambling is what gives gambling website more money and it's obvious, but having a dormant account in gambling is something that is different from my perspective,
As I may seeing dormant account in any gambling platforms, it doesn't grant any thing or bring anything at home, that is why i strongly believe that gambling get more money once people play more bet in it.
It's a win-win situation for the casino, here's I will show it:
1. If you leave your coins on the casino and didn't gamble at all, the casino will charge you some fees due to your inactivity (casino earn profit).
2. If you remember you have money on the casino and you want to withdraw it to your wallet, the casino will charge some fees when you want to withdraw your coins (casino earn profit).
3. If you remember you have money on the casino and you're want to gamble it all, since the house always win you will lose all of your money (again, casino earn profit).
In the end casino will make money, while you will lose your money. That's why you shouldn't gamble to chase more money.
As long as they give you information like that then it means it should be working fine for you. I am not saying that it is a bad thing to just charge people, it could be good because they are a business and their aim is to make money. Do you see Apple distributing phones for free? Of course not, so why expect a casino to not make money anyway they possibly could? Either from leaving the money in there, or withdrawing, or anything else.
Also they charge you a withdrawal fee because you actually do withdraw and there is a fee for the transaction which makes sense so they are not keeping it all as pure profit, they spend some and even maybe most of it on transaction fees.