The thread keeps merging two things, the selling and the headline. Strategy's sales show up in a filing on Monday for a week already gone, so by the time anyone reads 'Strategy dumps' the coins changed hands days ago and nobody noticed. The headline moved the price. The supply didn't.
Strategy is another buy the rumour sell the news, the dude has been announcing his bitcoin sell off for a long time, it's not an institutional move and transactions settled over the counter.
Real institutional move is buying ETF in billions without announcing anything, by the time they filled their bags the price is already going up.