cashing out

[Tomatoes]

The following quoted text is from http://www.playwinningpoker.com/online/poker/

"Cashing Out and Your Internet Bankroll
Another artificial problem the online cardrooms create out of necessity involves cashing out. Suppose you have carefully charged up a $1500 bankroll, and you have won $800 in a week. Not bad. You want that $800 in your pocket and you want to make another similar amount the next week. Well, you can't do it. The cash out rules require you to first pay back your original deposit method, and then get sent your profit. So, to get your $800, you have to pay off that $1500 you sensibly charged up, leaving you with a zero bankroll [ballance?]. It's a bit complicated, but in essence, cardrooms require winning players to play on their profits, not on their credit cards."

Have any of you experienced this? I don't get it; how can the casino know if you have paid off your credit card?
What if I want to take $1500 from the casino (leaving the $800) and pay off the credit card. It doesn't make any sense (from the casino's point of view) for them to stop me from doing this and of course they should have no right (legally or otherwise) to try and stop me from doing it. wtf?