For anyone on the outside looking in the admissions process will not necessarily seem logical or fair, what ever fair actually means. Unless there are blatant disparities in someone’s academic credentials relative to the the normal ranges of accepted students there is always a reason. That is a good thing! Given what you have indicated you are clearly bright, you believe you weren’t worthy based on your GPA, you clearly had other positive elements of your application that were compelling and valued that more than made up for your supposed low GPA.
I appreciate your feelings in regard to your good fortune versus the results of other friends or peers. That shows humility and compassion.
You are entitled to celebrate your success. Best Wishes to you!