Frankly, I feel that the shock comes from the fact that everyone was expecting the price to rise after the news of the ETF getting approval, or that the price would collapse if that approval was not obtained, but what happened is that the approval was obtained, and yet the price did not rise. The shock is more psychological than an analysis of the price.
In my opinion, the price would have reacted positively. Maybe we see Bitcoin move to claim the $50k level had the first tweet officially came from the SEC, and before we see price retrace downwards, but I kind of think that the SEC twisted the game with that tweet by coming back later to claim that it was not originally from them, and then later when the news officially came out to be that the ETF has finally been approved, plenty of investors already lost interest while some investors started playing the safe game, and the whole market were filled with FUD.