Crypto Conspiracy - What to make out of this

What the heck happened this week. I've been looking at coinmarketcap for years but never have seen something like this:

Nearly all cryptos declined in price and just magically happened to rise at the same time. I don't believe in coincidences and I am not sure what to make out of this. What are the reasons that this might happen?

A selloff in Ethereum within 9 hours alone equates to about 3,5% of the total circulating coins and about 1 Billion dollars. Does Goldman Sachs have trading bots?

Opinios are appreciated :)