You are so misinterpreting the world. There are people who only review when they are facing an issue, and if they are happy they think there's no need of review because they got what they paid for. I wouldn't judge a customer as having abusive nature even if he has 100% negative reviews..
I think the abusiveness is primarily in the guys forum post, plus posting the negative Amazon review without waiting for response from the developer.
But that's just my sensitivity level.