As others have pointed out, this is simply their way of making sure that they have a payment method on file for when your first free month is over. It's the same thing that every other major MMO does.

And really, it is absolutely unacceptable to flame each other, regardless of how much you feel that the other person is a troll/idiot/asshole/whatever. If you feel like they're a troll, report their post. Don't respond, just move on.