I doubt, however, that there is a player so big that he can manipulate all exchange data.
Be serious!
Whales can only manipulate the price of a certain coin or the whole market but datas and volumes are being manipulated by the owner of the exchange . They say that cmc is also manipulating their data's but some says that cmc is only synchronizing its data on other exchanges so cmc is not the real suspect here .
Not all believes on the datas that they see online so this does not affect the price of cryptos too much but the price manipulation of whales do have a major impact on the coin or on the market .
I don't think all whales will do the same because I am sure that some whales still doing a good thing related to the market. But yes, the whales can do whatever they want because they have a large of funds so they can move the market to one price that they want.
But I don't think that exchange market data manipulation will bring the whole market is going to down because if we take a look at the market, especially big exchanges, they are serving the data that is happening in their site. I think they give real data to traders so traders can see what is going on in the exchanges. Traders will only use the data from the source they know.