"By definition if you have been indoctrinated - as many religions do from an early age - then it is not a choice or a formed/informed opinion."
Yes and no. I was an indoctrinated catholic. But, luckily, I was also educated and exposed to other ideas, giving me the opportunity to change my views on the matter. I can say the same for many of my peers.
Indoctrination isn't just the early-age stage (although that is foundational), it's a continuous process. And indoctrination can be broken by education and life experiences