Thats because as insane as the Republicans are, they are completely sincere and really do believe the insane shit they say. Democrats on the other hand will say anything to grabs votes, and then do whatever benefits them the most once in office.
So all they need to do is ship all the phones with a preprogrammed private key, this way its decryptable when its sold. Then give the user the option to generate a new key during the setup process. Still secure and does not violate the text of the "law".