Because you obviously did not get affected by your upbringing, because statistically people with a poor upbringing like you describe from your own experiences, of abuse and bullying, achieve very little, and under perform in every measure.

Because the system let them fail, if i didn't do what they asked me to I was on the streets. It just simply was do X so I can eat. My failure to just give in and die is why i'm here not due to any willingness.

Your own intelligence and willingness to continue the pursuit of your degrees despite hatred towards it resulted in your career. 90% of people would have quit or picked another major if they were in your shoes, and people of below average intelligence would never have gotten anywhere near a passing grade in any meaningful cryptography/advanced discrete mathematics course anyway.

You're kiding right? Most people pass because they get the answers to the course from the year above like everyone in my year did and just substitute the numbers as they've been changed. Shit doesn't really change maths wise so its not like they can adapt the syllabus/questions much. Then its just memorising test answers and being able to sub in numbers as appropriate.

I got given a degree essentially with no personal investment or effort. I just turned up.