They may be basing it on the fact that Gaston's is not listed on the 2013 DDP brochure as a CS restaurant, whereas Be Our Guest is.
That might indeed mean Gaston's won't be accepting the DDP. It might also mean they won't sell full meals. Right now there is no real confirmation on either, as a full menu has not been released. The only thing that's been released so far is a frozen apple drink and cinnamon buns. And if they only serve snacks, like Sleepy Hollow, it won't appear on the brochure.
But it's worthwhile to wait and see what Disney announces, rather than an unofficial website. Unless somebody at that website knows something that the rest of us don't know yet.