It's just that there are gamblers that don't really do research before registering and doing deposit in a casino. Most of the time, they only do research when a casino is showing sign of being a scam casino like delaying their withdrawals, forfeiting, and constant reasoning of casino why they can't let you withdraw. Their marketing team is just so good that they still able to lure some gamblers into their casino and scam them. Once you deposit in this casino, you can consider yourself a loser even if you won in their games.
1xbit plays cleverly as they do not scam initially. When a person opens an account at 1xbit, they do not scam, they just let himself have a good natural experience of gambling, depositing, and withdrawing. They usually will scam selective people who have large amounts in their bankroll or deny the people of their earnings through big wins etc.
If you are not a bitcointalk reader, it may be not easy to guess that 1xbit is a scam until you experience yourself by depositing and then your account gets closed and your fund gets stolen by these scammers.