Can you provude the ToS for that promotion. How the heck you manage to wager the bonus while you don't have any deposit on that casino? On what kind of promotion you get that bonus money? It seems a very weird promotion to let user play using the bonus while they will not let the user withdraw unless he will deposit same amount of money. I think that's very suspicious same with the casino indicated on the screenshot.
You should not be able to play unless you will the minimum requirements to get that particular bonus. Just a hunch but the casino is very shady. Keep away.
Do not judge if we do not know the full terms and conditions related to the bonus. Every casino has their own terms about bonuses especially no deposit bonus. In this case we should know about the no deposit bonus which is taken by MNbag before judging the casino too far away without clear information.