But one could not do that and be just as vulnerable. Same as you can use a PIN on BitLocker and be safe in this case.

Right, but BitLocker is vulnerable by default whereas LUKS is not, because BitLocker relies on a TPM without a PIN by default whereas LUKS relies on a password by default. Yeah, technically this attack ain't BitLocker-specific, but I don't know of any other FDE implementation that defaults to using a TPM without a PIN/password.