Great questions and thanks for watching. The body of knowledge surrounding technical analysis is enormous and very subjective, it's definitely not a science. Ultimately it reflects investor (or trader) psychology and as I try to convey regularly, is a tool. Some of the oldest techniques that I've studied are candlesticks which have become almost ubiquitous in charting software. The origin of this analysis is centuries old dating back to Japanese rice traders. It's hard to imagine doing this pre-computer but it has stood the test of time.
With regards to the miner meeting. In my opinion it all comes down to uncertainty. No matter what it is being traded: BTC, currencies, equities, bonds... etc. people hate uncertainty. I remember trading securities back when the FOMC (the Fed) would issue press releases about rate decisions and the markets would literally come to a standstill because whatever was about to be presented would have tremendous impact; but it was unknown. The following volatility was something to behold. You can go back and look at charts of FOMC days and it's unreal. So there seems to be alot of uncertainty in BTC right now which I believe is the fundamental reason driving the selling pressure.