A selling club is a club which has, as one of it's main policies, to develop and sell players on to bigger clubs.
Just because it happens on occasion, for various reasons (moneyhungry player + world record fee in the case of Pogba, Vidal wanting Bayern + Juve fed up with Vidal's off the field problems in the other case), doesn't make us that kind of club. Our ambition is to dominate in Italy and challenge for the Champions League.
If you believe that Juve's project is only to feed the filthy rich clubs, then I just don't know what to say.