zahavasdad,
Saying we are all sinners and need to do tshuva sounds very similar to a philosophy of a relgion started by a man whose big birthday bash is coming up this weekend
+1 to DaasYochid’s response. The “we are all sinners” philosophy is not where the birthday bash religion errs. Rather, their philosophy states that teshuva is worthless, and man must therefore accept their avoda zara in order to be “saved” from eternal torment that is due to man for even the tiniest transgression.
The Torah teaches us that Hashem accepts our teshuva lovingly and desires that we come close to him, and that work is meaningful even if we are imperfect creatures. And that Hashem is fair in judgement, not a sadistic tormentor.