It looks like Palantir is blaming FBI's mismanagement of ACLs as the root cause of what happened here.
Complaining publicly has no downsides for palantir here.
The complaint can have a real ramifications ( loss of future contracts and so on ). That said, at certain point enough is enough I suppose.
Whether the government purchased a defective product that was insecure or misused a good product, the government should be held to account for the failure, same as with any company.