It's because many gamblers can't accept that they lost significant amount in gambling and then they will accuse the casino (in general) that they got scam. This is the problem if you risk the money that you can't afford to lose, it's really hard to accept the bad result specially if you're expecting the opposite.
Anyhow, if the accusation has basis and legit, there should be concrete evidence to back up the claim in order to address the issue.
I say there are some issues and if you have significant proofs your issue will be resolved by the team but if you are putting mere allegations without any base just because you can't handle your loss is not gonna help you in these cases.They think they can harm the image of casino but in reality are wasting their time so don't give them importance.