I still want to see a dozen ranger veterans vs http://fallout.wikia.com/wiki/Gojira
You know it is Caesars policy to kill all Followers and educated people? He is showing weakness when he doesn't follow his policy.
Where was that put down as Caesar's policy? nowhere. All of his advisors and spies are well educated people. And its Lanius's rejection of subterfuge and sabatoge that would cost the legion victory.
To break the policy, it shows weakness in his resolve, and the resolve of the Legion, and the Legion must be resolute.
Then the legate is also weak because he'll break the same policy for a female courier.