I think people are turning their alts into bitcoin in the hope of ETF approval and bitcoin will rise and buy back their alts in much less satoshi than now.
That's pretty dead at the moment. I'm not sure where the optimism comes from.
If people have been dumping their alts (enough for this sea of red anyway) for Bitcoin, Bitcoin price should be surging. Instead, the $6000 support was broken for the first time in I don't even know how long. From those tidbits, one can probably conclude that money is leaving the market that and every coin is doing horribly, with Bitcoin much less so than alts.