Agree that while "they got swept up in the moment" is a reasonable theory (Hanlon's razor and what not), it also seem very plausible that they knew it was risky but not how risky, and felt like there was still a positive expected value because they would be able sell their coins early (I saw a tweet about how a16z is still up 5x on it's crypto investments because of this[1]).
I suspect that's the most plausible, least "evil" theory. Although that still leaves them knowingly gambling that bigger fools, who they intend to take advantage of, will come along later, so I personally wouldn't consider that "good". But I also won't deny it's a dog-eat-dog world at that level and everyone playing at that level is already aware and taking that into account. In that case it just turns out they were the dogs eaten instead of the victors.
A cynical, but not entirely incorrect, take could be that greater fool theory is a pretty critical part of the VC model. The final fool in that process being when they offload to the public markets.
[1] https://twitter.com/mims/status/1592934095117426689