Maybe you just can't do this, but for somebody to tell me that they treat these people with respect and I'm doing it for self-gratification, or whatever the issue.... For you to study that, though, you don't follow up with the actual person they bought the service from to find out if that person was telling you the truth or if they were violent—whether physically or verbally or any other way—if they refused to pay, all those other things.
There's no way for you to know whether what they're saying as buyers of sexual services is actually what they do when they're behind closed doors in a consensual adult situation. Does your study show that?