The true religion is individualistic. I recommend looking into Jefferson's letters, April 1803.
Thomas Jefferson -
"Dear Sir: In some of the delightful conversations with you, in the evenings of 1798-1799, and which served as an anodyne to the afflictions of the crisis through which our country was then laboring, the Christian religion was sometimes our topic; and I then promised you that one day or other, I would give you my views of it. They are the result of a life of inquiry and reflection, and very different from that Anti-Christian system imputed to me by those who know nothing of my opinions."
Henry T. Laurency -
"For the true essence of religion is individualistic, and the form is the individual’s private matter corresponding to an individual need."
Alfred Rosenberg -
"What Hitler's own beliefs were he never told me in so many words. Once, at table, he said a high-placed Italian had asked him point-blank what his religious beliefs were. He had begged permission not to answer that question."
Jefferson -
“I am moreover averse to the communication of my religious tenets to the public; because it would countenance the presumption of those who have endeavored to draw them before that tribunal, and to seduce public opinion to errect itself into that inquisition over the rights of conscience which the laws have so justly proscribed. It behooves every man who values liberty of conscience for himself to resist invasions of it in the case of others, or their case may, by change of circumstances, become his own. It behooves him, too, in his own case, to give no example of concession, betraying the right of independent opinion by answering questions of faith, which the laws have left between God and himself.”
All those who heeded the calls of Reason AND Life understood that all historical religions have been the outcome of some profound vital need, outfitted for a specific group or race of people, practically teaching the same thing. Christianity was not the first to preach honorable brotherly love and it will not be the last one to. Truths can be found in all existing religions, the religions merely differ by time, geography, and the intellectual development of the people among whom they arose. All the religions of antiquity and the pagan religions had the same basis of Truth.
The falsity of the Abrahamic religions, particularly the proselytizing Christianity and Islam, is in their claim to being an universal religion, meeting universal needs, and in their unwavering ambition for world domination. Does Islam fit Europe like a glove? Did Christianity "save" the indigenous peoples of the Americas? They have demonstrated their total impotence in their inability to counteract the spread of Evil. They have even failed to reconcile the existence of Evil with the existence of a benevolent Deity. The conception of an entity in opposition to the Deity (which was a thing before Christianity came into existence) has only increased superstition, uncertainty, fear, enmity, and paranoia. I do not deny that demonic entities may exist, but to say that the whole world lies under their control is blasphemy.
The aforementioned Abrahamic religions have foisted unto the rest of the world a negative conception of the world, with an increasing emphasis on the afterlife and a dependency on the Deity. God does not do what man has to learn. This should have been made perfectly clear by WW2.
Julian, Celsus, Porphyry... it's no wonder why their works were destroyed. They saw, as clear as day, the way to destroy Christianity: by dissecting and attacking Judaism. Rationally, not emotionally.
Of course, I bear no ill will towards Judaism. Julian certainly didn't. There are actually a great deal of truths preserved in the Old Testament, which are rarely brought to the surface since the Christians have made the Old Testament, in the eyes of unbelievers, a book of no consequence. Granted, it is quite primitive, archaic, and barbaric in some areas. This can be easily explained: the Jews came across many ancient cultures and appropriated from them, and were also taught by them. They were even inclined to worship the pagan gods. Whether they were harmless folk or parasites, their development under these empires was truly a learning experience compared to their development under the Christian yoke.
This is plainly seen in the development of Jehovah/Yahweh. He was, at first, a pastoral deity, then the god of the Patriarchs, then a national deity, and finally the one we have today. With the advent of Babylon, he was given cosmic properties. The transition from a barbaric to a loving god can be explained through this manner as well. It should be noted that some of the dialogue was them putting words into their deity's mouth...
Julian praises Abraham for his faith strengthened by divination. Joseph was considered by the Egyptians as one of their own and he practiced divination. Moses was born, raised, and lived as an Egyptian for many years. Like Akhenaten, he promoted the worship of one God and made it exoteric. Since the masses were inclined to build a golden calf, and serve a dozen idols, it should be clear that this worship was not initially accepted by the majority of Jews until a later period in their history. A comparison of Atenism with Judaism reveals the similarities and differences. Judaism was meant to bind Jews together while Atenism was meant to strengthen political power of the Pharaoh. Moses initially forbade worship of other gods, he did not deny them. Julian mentions the offering to the Azazel. Whereas Atenism was envisioned as a "monotheism of knowledge", absolute knowledge of the one God. Moses' contact with the true Deity was the turning point for Israel. Originally, as their prophet Amos plainly states, they had worshiped Saturn/Moloch/a star deity, like the rest of their neighbors. This is specifically stated in Deuteronomy 32:8-9.
What the Kabbalah and the Jewish philosopher Philo have to say on the book of Genesis is remarkable. It adds much dimension to the account, truly more fascinating than the naive Christian theological interpretation of it.
Two things to take note of: increasing overpopulation of humans was tolerated (Genesis 6:1), 120 year space given for repentance (Genesis 6:3).
The Flood myth can be found worldwide, but no global flood took place? Then it must have been some catastrophe that affected many nations, everyone remembered it and transmitted to posterity. The sinking of Atlantis comes to mind.
Anyway, a Jewish heretic, who renamed himself Paul, is basically responsible for the chaos of two thousand years and it is this Christianity of his which bears the "greater sin". Christianity has hindered the development of the Jewish race for centuries. It has also supplanted symbols with meaning for dogma devoid of all meaning, reverence for the futile observance of outdated customs and rites, truth for a pack of lies. If it really had good intentions in it's beginnings, then it would have built off of what was then existing, removing only what was unsuited. Christianity stabilized at a later period, when they turned pagan temples, symbols, etc. into their own.
The Christians have forcibly enthroned the Nazarene and corrupted his simple teachings of universal morality and divine son-ship. They have betrayed him.
Where did the Jews get their racial laws, monotheism, and the conception of man being "made in the image of God"? A combination of their contact with the higher truths of Egypt, the burning bush episode, and at Mt. Sinai. Revelation is never given in fullness, it is gradual. Christianity assumes that the Bible was the end of it. Period. They are wrong. They only have a small, tiny portion of the truth, which has been mixed with countless errors and superstition, which they elevate above all others.