This is not new information, though I was surprised at the wording of the post as well. The wording of all their documents, since 4e was released has implied that anything posted, using anything official 4e, was unauthorized and possibly illegal, unless you're working, licensed, under the GSL.
I have had an open ticket with Wizards Customer Support since September 28th, asking them to clarify their position on the Monster Builder specifically. According to their EULA, at least it seems, you are not allowed to post, or distribute, in any form, any Monsters built with the Monster Builder.
Even though there are two export options, and theoretically a third on the way, and members of the official Wizards Community, were encouraging people to post Monsters there.
I have received two updates, since sending in this request. The first informed me that they were escalating the request and I would have a response within 48 hours. The second told me they were still looking into it. It has been 11 days since Ive had a response.
This is only after the question went unanswered for 2-3 weeks on their official community.