When liquidity gets pulled from the market for any reason, be that uncertainty, momentum, or completely unrelated things selling off for their own reasons, de-leveraging occurs systemically.

A shitcoin tanking 90% can draw down Bitcoin as the shitcoin holders liquidate anything else they might own to save a margin call... or the margin call itself liquidates their other positions. ETF's extend that now into the stock and bond markets.

Like everything else, this is good for Bitcoin, as it is a gravity-well of liquidity it draws down less and less compared to other things over time which begets even more liquidity. It's often compared to real estate, which if you try to liquidate a large property it can take months or years... Bitcoin offers instant liquidity.

Most of the blood Friday was in perps since Binance was exploited via a stablecoin market, perps are all leverage which cascades as liquidity is removed.