Noveria: Espionage intimidate bug
My Shepard has rank 12 in both Charm and Intimidate and so should have all of those dialogue options unlocked. During the mission 'Noveria: Espionage', if I talk to Rafael Vargas and proceed along the conversation tree until the last dialogue choice, I am unable to select the intimidate option despite having maxed out intimidate. I have read that this bug can also occur with the charm option. Seems to be yet another bug left over from the original release.
As I say in a response below, even with both Paragon and Renegade bars maxed out, I was unable to select the Intimidate option.
The moral system is not solely based on the points you spend into charm and/or intimidate.
Many dialogue options depend on the actual number of Paragon/Renegade Points you have, and your Renegade bar is almost empty.
So this is not a bug, you just don't have enough Renegade Points to get the Renegade dialogue option.