If the product was installed using GPO, then it can only be uninstalled using the same GPO. Deploying the product through GPO is the recommended method. Obviously, a lot of environments use different software management systems, so this will not apply for everyone.
To uninstall the Drive Encryption product, the system must be decrypted. It requires client administrator credentials to decrypt the system, and a local admin would not be able to do so unless they had access to those credentials. This should be enough to prevent uninstallation for non-GPO applications.