I was enough to assume there was some bigger picture that had in mind, some "ends justify the means" reason for all that secrecy and all those atrocities.

Turns out it they are just an unaccountable and drunk on power enforcement division serving the ruling class whose "big picture" is more yachts and pedo islands.

I had a very similar experience. I got swept up in the post-9/11 jingoism. I felt I had to prove I was the Yankeest Doodle Dandy that ever lived and not some "terrorist" since my family is south-asian. My family isn't even Muslim but that didn't stop the racist remarks.