When you win the casino loses money, the supervision is not happy and tells the dealer how unhappy they are. For the dealer it's a no win situation. I was informed by an x- dealer that they call these casino's sweat shops because the dealer is sweating it any way it goes. When charting a table to play you will notice all types of dealers. Some are better than others.
Some dealer do spin the ball at random, every release is a new place on the wheel.
The dealer is a person just like you and me. Going to work to support there family and make a simple living, most are under paid. So tip the dealer if you win, be friendly to the dealer, after all he has a boss breathing down his neck and we all know how that feels. Don't take it personal that he is trying not to let you win. Don't try and break the casino, it just makes you a target.