1. the behavior directly conflicts with one's beliefs, values or morals
2. the behavior harms another person
3. the behavior is illegal
If any one of these requirements is satisfied, you're probably deviant. But, as I stated in the first sentence, it can only be determined in a group setting.
It all boils down to eliciting behavior. If someone likes something, and it doesn't violate the 3 rules of deviancy, AND you know you'll achieve a certain outcome or response, why would you NOT take part??? Food for thought...