The example is > For the last 25 years, engineers have said ‘we can make it secure, or we can let law enforcement have access, but that means the Chinese can g

The example is > For the last 25 years, engineers have said ‘we can make it secure, or we can let law enforcement have access, but that means the Chinese can get in too” and politicians reply “no, make secure but not for people we like”. Insecure police departments will inevitably leak the backdoor keys. It's not possible to limit who can use decryption keys based on who they are and not just possession of the keys under our current understanding of how encryption works. If you assume that the police will never leak keys then sure it's easy. But arguing about whether or not social factors like police department computer security is good enough to safely store keys is a technical argument about this technical problem.