If Neteller had the attitude that "Oh, we're only the service provider" for every situation, I would understand why they might not want to get involved in payment disputes.
The problem is, Neteller has no qualms about disclosing personal info and shutting down personal accounts of players that they (or a sportsbook) suspect are scammers, but they do next-to-nothing to help get rid of stiff books.
That's the piss-off - if they want to try to cut down on the scamming, try shutting down some of the stiff books, too. One scam book will steal more money than 10 scam players will.