They did the exact same thing when they added the Netlix app to the V6 box. They even started advertising it to new customers in a manner which intimated that a Netflix subscription would be included in your monthly subscription to Virgin, which was obviously really misleading (just like this Prime footy deal).
You can arrange for your Netflix subscription to be collected by Virgin Media along with your Virgin sub's, but yes, they do have a habit of inferring you cannot get the exact same services without Virgin Media being involved.
Why is this even in the Virgin Media cable TV section of the board? Surely it is something associated with Amazon Video and not anything at all to do with Virgin Media?