I consider slot machines no more predatory than the workout equipment advertised on television. I rarely watch television anymore, because I find it awfully distracting and the amount of shameless advertising on the waves I find revolting. The ones that humor me and disgust me the most are the advertisements for workout equipment. It is always some silly device that promises the most insane results. In the commercials, the product is always demonstrated with some person with the body of a demigod. The unspoken promise is that if you use this device you will look like this model, as if this device is how this person who spends hours in the gym got into such great physical condition. However, the product to promise something to the people that use it, however the product maker is knowingly making a lot more money off of people that may use it for a week and then will retire it to a junk pile in their garage.
This is the same premise under which slot machines operate. There is a legitimate promise of a chance at winning big. However, it is well known by the casino operators that they will be making far more money off of the people that will never see a dime than they will spend in payouts. Both of these marketing plans are feeding off of a sort of ignorance. You cannot attack one without the other. Neither one is really considered wrong in the open market that has become the most identifiable part of American culture.