Why Is There So Much Difference?
Brother first of all, be relax as getting such thoughts naturally and wondering with sincere mind is not wrong, it isn’t blameworthy, it’s a natural phase. Yes you’re right, that many factors are outside of a human control. Many are under some control. Allah never holds someone accountable for the factors that were not under control. If someone gets born in a Hindu family and he was being sincere in finding the truth what innocent mistakes he commits either in belief or in understandings that cause wrong action, he won’t be held accountable for those mistakes. Only what we know and sincerely do according to what we know, is where we are held accountable. Whatever human it is Muslim, Sikh, Hindu. If his attitude is sincere towards finding truth of creator and he’s not negligent or trying to deliberately run away from truth then this is good, where ever he lands with sincerity, Allah will take matters with justice, not injustice. But where deliberate wrong behavior (either in belief or action) happens or where not, this is known to Allah. We only know that no sort of injustice would be done AT ALL. For example you may know that a person killed someone with car hit because brakes failed, and you might think that he’s innocent. But the judge might punish him because there’s another fact that is known to judge. That is that this man deliberately removed oil from brake compartment so that it definitely fails and kills someone while driving. Similarly we might only know some factors externally, but majority of factors and all the matters of heart are known to Allah. That’s is why we Muslims never judge who’s going to hell and whose going to jannah. A Sikh dies, we won’t say he’s going to hell, because we don’t know if he was actual disbeliever (the one who knows what the truth is quite clearly but still chooses to disbelieve) or just a sincere person with mistaken understanding because of his circumstances that were out of his control.