I have to say, this ruling seems really bad to me. This goes entirely against how the card reads - the card lets "you" make the choice, i.e. the owner of the card (exactly how every other instance of "you" is used in the game). It makes no sense at all for the opponent to make that choice instead of "you". It's completely counter-intuitive - I guarantee that nobody has played that card that way before this very moment, and nobody who doesn't read that clarification at the end of the document will EVER play the card that way on their own.
In every single card game, "you" refers to the controller of the card. Making a blanket rule that "all optional effects are chosen by the active player despite what the text on the card actually says" is a really hamfisted way of fixing the card if they printed it wrong. Just let people resolve the card the way it's printed, or errata it to not be optional, at least, so that people will USUALLY play it correctly even if they miss the FAQ.