What I see is a lit of users complaining when they just loose a little. If you see how much High Rollers win last weeks then it looks like its all fair to me. If they would cheat they definitely do it at the high rollers and don't let them win 50 BTC in a few hours.
But if you believe they get rich by screwing low rollers, you need a doctor.
The only high roller I see winning is probably the same person (negan/noctis/sin/others) and could be allowed to win to entice people. They lost 60k 1 day and said in chat 'its only money'. Next day showed up betting shit loads again and won. Then when someone asked for $1 from him he said no. If he's so rich to not be bothered by losing 60k, that's odd behaviour. Infact nearly every high roller is a loser. How often do you see a random high roller show up betting moderate amounts and win 3-4 bets in a row? Not often. How often do you see them lose 4 in a row and bust. Very often.