The old adage "The client is always right"
comes to mind.
Let's say you buy a new TV, take it home, plug it in, and find out all the colors are out of whack and there's an annoying stuttering.
Now, the very next day you take the TV back to the retailer for a refund, and the guy at the shops tells you "If you stick with it, you'll get used to it and end up enjoying it".Which bodily orifice will you ask him to shove the TV up through?
Gamer Culture, being Casual or Pro, male, female, old, young... It is all irrelevant. If you want to sell a product, it's your responsibility
to make sure the product meets the client's expectations, and it's a pretty big faux pas
to attempt to shift blame to them.
If people are returning the game before 15 minutes are up, then there's something pretty bad about it, be it unintuitive gameplay (never understimate the need for tutorials), glitches, or the game simply being boring. It's your job to fix those issues, not to coach users on proper gaming etiquette (hint: there is none
As for piracy, it will happen. Accept that. As Hima and ANtY said, piracy is an indicator of interest in your game. Just put a dunce cone on every character's head if the game fails to be registered and go on with your life.