Much of what MMs do could be seen as "manipulation", because part of their job is to maintain an orderly market.
That sounds like a form of manipulation to me particularly when they are the only ones who can bid and ask at the fifth digit but......OK.
Consider this: let's say Koch is selling a very large number of shares. If he just dumps away, the stock will bottom. If he does a negotiated sale, he'll make more money, and the stock will remain relatively stable.
Is it legitimate for the MMs to create that stability? I think so, because a single person's desire to sell shouldn't be taken as a legitimate indicator of market sentiment.
Market Data 
Markets 
AI
