Do folks think that this was utter negligence by the VCs, or just a pump and dump?
neither? Negligence doesn't make sense because it was the VCs own money- no duty to care. It doesn't seem like anyone cashed out either. Seems like a bad bet that went south.
Almost definitionally, VCs are investing someone else's money (the people providing the capital are called the "limited partners" (LPs); the VCs who raise and invest the money are "general partners" (GPs).) The LPs are often pension funds, university endowments, and charitable organizations.
Yes, GPs do typically have a capital contribution requirement, but it's generally in the area of 1% of the fund, so the vast majority of what VCs are investing is other people's money, for which they definitely have fiduciary responsibility.