the theory described on reddit makes sense just if the volume of BTC one investor is able to move is big enough to have effect on the price in the markets which is hard to happen for BTC market.
my 2 cents of old stakeholder ;)
(btw, I bought bts today ;) )
Institutional investors buying derivatives and dumping can certainly affect the market. As an example, the gold and silver derivatives markets completely dominate the prices in the physical markets.
I don't know the volumes for the btc futures. It seems hard to believe for me that investors in btc future (even istitutional investors, if are there) are able to influence the price of btc - btc has a daily volume of 10.5billions (today), you have to sell big numbers to move the price.
but, who knows?, theorically it is possible.