Yes, but the really weird thing is that they seem to:
a) believe that what they're creating is a basilisk, and b) keep trying harder to do this while staring right at it
I think they're very deluded about (a) -- but if they do actually believe this (and it really seems like a decent proportion of Anthropic truly does), then why keep doing (b)?
That seems to be why this individual resigned, but I'm surprised it's not all of them. The cakeism is strong in that company.
He was referring to this basilisk https://en.wikipedia.org/wiki/Roko%27s_basilisk
In short, this is the believe that a god-like AI could punish them retroactively, for not having done all that was in their power to create this AI.
(A bit similar to some religious believe that a god could punish you after your death if you did not spend your live "pleasing" said god during your life)