If it is wrong for the owner to give the loan then the borrower is more guilty. Since the owner operates a casino or gambling business, he can certainly provide loans to grow his business. On the other hand, the person taking the loan should also be aware of whether he can repay the loan amount or not. When providing loans, sometimes such situations have to be accepted. It would have been better if the financial condition of the borrower could have been well known before giving the loan, then it would have been possible to prevent such a situation.
This is far from a fact. In most countries, gambling and lending are completely different areas of activity that are regulated in different ways and you must obtain different licenses to carry out these activities. That is why the chances of the casino through the court to demand money from this gambler are very low - they did not have the right to issue him a loan (this is my proposal, but I think it will be true for 95% of countries).