He did not talk down the club. When a player today perceives Bayern as more competitive than Juve then that is normal and no different from how almost the entire football world sees the two clubs. They have great history as club (no plastic), have a gigantic star studded squad, are the second most consistent side in Europe after Barca (1 win, 2 finals, 3 semis in the last 7 years), massive following, they hire the best coaches in the business, are default league winners, have excellent management and massive finances that ensure the continuation of their success. If Vidal had said these comments in 2003 I'd be surprised and offended by his statement but no one should be surprised or offended today.
Apart from that statement (which should not be very controversial), he has always spoken well about his time at Juve, and congratulated us on every occasion. He never even took any jibes at us after they went through to the semis and when he did wear the Juve shirt he always gave 100%. I don't see his move as very different from Zidane's in 2000. If anything, we were closer to Real then (2000), than we are to Bayern now (financially, european consistency, squad quality and size, management quality).