First, from the moment you can manipulate Bitcoin, you can affect all other digital currencies, this is very clear for anyone who goes on to analyze the digital coins.

answering the second question: Everything is about money control. Bitcoin is seen as a threat by these large financial entities, as soon as the digital market starts to grow dramatically, people's capital will begin to flow to these assets, as a result, "fiat" money will become a certainty it is useless, because fiat money is also about something with subjective value, that is, its value depends on the trust people have in the person who issued the title. With this, these great institutions will no longer have the control they had over people, something that today is possible through "fiat" money.

Contrary to what you think, such manipulation is not something people notice easily, many individuals in this and many other markets are not even sure how they work. People do not know that many things that are around us have no intrinsic value, that is, that asset only has that certain value due to the sums of various subjective tastes that resulted in that.Thus, making it easy to manipulate things, and most people understand them as conspiracy theory.