Kids are smart, very smart. She's heard daddy telling Alexa to get something, probably many times, so she repeats that process. Once Alexa responds with a list of dollhouses, it's not difficult to say "buy the first one" and have it finish the order process.
And nowhere in the article does it say that the anchor's words ordered dollhouses, only that it tried to order dollhouses. It also probably caused Alexa to respond with the list of dollhouses, but most people would regard that as trying to order something. It doesn't have to actually result in a finalized order to be called trying to order.
And +1000 for using the PIN, very disconcerting to wake up in the morning to find a drunk forum post, how much more so if you find a drunk order for 2000 inflatable Heidi Klum dolls.