At this stage I'm inclined to chalk it up to ignorance and herd mentality. Someone mistakenly thought the hash rate dropped alarmingly, not realising it was just lousy metrics. It gets reported in the media without being fact-checked. Speculators panic. Snowball from there. Lots of fuss about not much.
I hate to be Mr Contrary (or do I
), but the evidence for a speculator panic is also a bit thin. Normally, big price movements cause mempools to quickly fill up with panicky transactions, and
especially for transaction fees to go up, that's the real sign of people sending BTC to exchanges in a panic
yet neither of these things happened, mempools have been pretty quiet, and certainly not in expensive fees territory (do you call 35 sat/byte expensive? I don't, and neither do the fee panics of 2017 and 2015)
I dunno, you could argue "segwit capacity increases stopped that", but blocks weren't alot fuller than recent averages (coming off the back of alot of 900kB blocks per 24 hour averages recently...)
So it's all thoroughly mysterious. The sort of people that leave all their BTC on exchanges are those who have personal/political connections to the owners (i.e. they get to keep their coins if there's any fraud, because they're in on the fraud). So if those people sold to create all that volume, then they got scammed by this. That sounds unlikely.
Are we really to conclude that in 2019, every idiot speculator is keeping pretty much all their BTC in their exchange account, even after Bitcoin became more well known for exchange hacks/fraud than for almost any other reason? It all sounds a little thin on credulity, no matter how you package it up