of course, I have experienced the occurrence of such manipulations, I once traded on an exchanger and the price of the token I had was manipulated by the existence of fake trading volumes, fake trading history and others.
It is true that the market can be manipulated for a moment. I've also seen events like you said. In my opinion, it is certainly very detrimental to certain token owners. So in the future we may have to avoid market manipulation as happened before.
This kind of manipulations and fraudulent schemes will always take place. Some of these frauds are really clever and cunning. However, I think that it is not possible to create long-term artificial demand because it can attract speculators instead of real followers.