How can they all crash at the same time?

These crypto currencies (and, take your pick, LINK, AAVE, etc) all function in very different ecosystems, from where the liquidity is sourced from to how long it takes a transaction to occur, to say nothing of confidence in their respective markets, we all know Bitcoin leads the way but correlation isn't 100% for any of them and even when it is, I would expect there to be a lag between the crash of one of the crash of another even when it's for the same reason.

I realize this is from Coinbase and not the real measure but can someone explain it like I'm five – what is it that is happening from a digital mechanics standpoint to explain why they are displaying a price that is so clearly locked for a major drop like this? Also what caused the specific drop at that specific time today?