You start from the premise that all religions are equally valid and that all practioners of religion are equally self-serving and corrupt. That is your personal opinion, and cannot be proven in any meaningful or empirically valid way. Therefore, since your premise is not empirically provable, your conclusion is equally invalid.
You're entitled to your opinion, but then again, so are we.
If you were to do an unbiased study of Christianity, you would find that it is the only religion that starts out with the premise that man cannot save himself, and therefore needs a savior. That being the case, God makes the way for man to be saved, and all man has to do is accept it and be transformed by it. No other religion does that. God, being God, receives all the glory for it, and man cannot boast of what he did, which keeps man and God in proper perspective: God as savior and man as undeserving recipient, as defined by their original relationship, before man became unworthy of salvation apart from outside intervention. All other religions concern themselves with how man can clean himself up enough, be good enough, do enough good things, and earn his salvation. God says (and I paraphrase greatly) "You can't earn it, it is a free gift which I give you, but you must receive it."
Why is that so hard to grasp?