Annoys me to end that people see this as security. The only security this provides is financial security for Apple and whoever pays them for using the DRM on this thing.
Yeah. Apple's "security" basically almost always boils down to "please trust us that we implemented this the way we claim we did", with many things trusting Apple servers unconditionally — like iMessage "end-to-end encryption" where an Apple server manages keys. Such end-to-end, much wow. But FileVault was at least reverse engineered enough to prove that it trusts the end user more than Apple.