They could just tell the truth about it that they are charging withdrawal fee,
I don't think they ever hid that they are charging withdrawal fees. in fact, they are saying that they are charging withdrawal fees. you can check their ToS and you'll find what you are looking for on "Withdrawals". you can even see when trying to withdraw how much they will charge you for the withdrawal fee.
I think this is the right answer, I understand that people do not want to pay the withdrawal fee as this affects them, especially if they are gambling with a low amount of money, but at the same time if this is on their TOS and you accepted it before playing there then there is not much to do.
If you do not want to pay for those fees then you need to find a casino that does not charge them, fortunately for the OP there are several of them in this market which have a good reputation so he only needs to play there and solve their issues in this way.