BTC is still too much considered as having a completely independent ecosystem, as if it is being traded on an isolated island. For this reason, whenever there is a rise or a plunge, most people look within the ecosystem trying to find some explanation. Let's be honest what news we've got the last days : coindesk article or a silly reason as Chinese not gambling any more ??
With a market cap in the billions, BTC is already integrated into the financial markets. ATM the only reason why BTC is dropping is because of the outstanding news about QE. This decision will affect all markets from Africa to Americas to Asia, .... So, why would BTC be left out?
See the plunge of SP 500 in the last days:
https://www.tradingview.com/e/?symbol=CME%3ASP1!
Or take ftse index (London):
https://www.tradingview.com/e/?symbol=INDEX%3AFTSEWhen you zoom out, you will see the enormous rally on both charts.