Yeah google has by fiat down ranked entire classes of results and companies therein many many times... And yet Pinterest is exempt?
They'd have to disambiguate that from the obvious motivated reasoning that's likely to exist there too.
Even then, sometimes you know better than users when making long term bets about what you do, faster horses and all - it's part art and part science.
Average users are also not necessarily the best to optimize on. 99% of wikipedia users never write anything. Does that mean the users that write are relatively worthless?
!w <search> to search Wikipedia directly.
(semi-joking... but complaining about typing 3-5 letters is definitely a 1st world problem ;)
That is to say that Google image search is the real problem and not Pinterest.