Unless anyone can produce any real evidence of "manipulation" (which I have yet to see) having any effect on the market, these claims of manipulation must be considered to be fantasy.
People are very susceptible to confirmation bias. They see what they want to believe and tend to ignore evidence to the contrary. Read about
"street light interference" and be amazed.
... Of course, I have no hard proof, but it seems much more likely to me that it is happening rather than that it is not.
No proof --> fantasy.
... the potential will be there to manipulate the markets.
Potential? Maybe or maybe not. Again, no evidence --> fantasy.
I would also like to note that I don't feel that many situations that some people might consider manipulation are really manipulation. Just as fee-paying Bitcoin transactions that seem purposeless can't really be considered spam, placing orders can't be considered manipulation. For example, is a "sell wall" manipulation or is it just a large order? Are high frequency traders really manipulating the market by placing and canceling orders, or are they just gaining information or perhaps using game theory to compete against other traders?