I would actually be interested to know what the logic is here: the hacker clearly doesn't like AM, or they wouldn't be spoiling their rumored-IPO quite this enthusiastically, they also don't like the users they are threatening to expose; but they also appear to be really bent out of shape about AM's allegedly-dishonest-and-exploitative 'pay to purge the embarrassing traces' feature.
I'd be really surprised if the actual hacker(s) really had any moral stance one way or another. My money would be be on just pure financial greed. They see AM and it's customers as a paycheck. They see AM as a source of money and are applying pressure directly on them to pay up and/or shut down. They also pressure subscribers to pressure AM from the other side to pay up to not reveal their information.
In the end I think it will be a loss for the hackers and customers. The hackers aren't going to get their money. AM takes a PR hit but doesn't really care because they already run a website for people with questionable ethics/morality. Customers info might get released, but for the 3 people that are actually real, married, and their partner doesn't already know, the shit might hit the fan. For everyone else, no one cares. And if you're a paying subscriber to a cheating website with your own real information, you're already a fucking idiot and get what you deserve for being a dumbass.