Reapers killed billions of people, no way i was going to let them live, even if they would have help us. It was my goal since ME1!
This.
My paragon Shepard opposes TIM for the entire game, tells him how wrong he is and how difficult it is to control the Reapers, how control is a power we don't understand and shouldn't be able to use, etc. It seems like a contradiction for Shep to then ignore what he just finished saying and choose Control.