Because those elements aren’t the Godhead or the community or the links between, just administrative or philosophical ideas, or rites.
Both Abraham, Moses, and Jesus adopted preexisting priesthoods and rituals, the religion Jesus adopted from is the Mandaeans, still around (down to just 9 priests though). That’s the religion of John the Baptist. Quite pagan. It was never a central expectation that out rites, ritual, and ideas come directly from God, we tended to be rather pragmatic about these things, abd kept the elements of priestcraft separate from actual faith. That’s where The Dark Night of the Soul conceptions have a lot of legitimacy in the faith.
It’s also a issue on the part of modern atheists and neo-pagans, not to mention some uneducated Christians, that Paganism in the ancient world simply isn’t well understood. The line between Christianity and Pagan practices wasn’t nearly as dualistic then as we like to insist now, and there wasn’t as much hostility. I’ve seen many fools write absurd things, some with degrees, that obviously contradict written sources.
Christians never would (save for a few pro til Nietzsche an groups in Asia minor) sacrifice for another God or man, renounce God, denounce other Christians, worship another God, etc… unless under extreme duress, and even then, doubtful. But the vast majority either we’re converts or lived in communities recently converted, willingly. You don’t automatically lose your holidays, a Jew converting to Christianity is fully right and even expected to continue practicing Hannukah, because that’s his cultural origin. It isn’t expected someone else of nonjewish origins to break that tradition out. You obviously couldn’t keep the practice of a holiday to Kali, by sacrificing someone to Kali… but if there was a dance or ritual attached, and was causing extreme confusion in converts, a Christian priesthood is unlikely to abandon it, just modify it yo make it palitable.
Most of our practices in this respect are a maze of older practices. Doesn’t mean like some modern people would say that were really worshiping so and so, just we entered into the arrangement with eyes wide open, pragmatic.
The church, every ancient church, be it a Catholic or orthodox rite, has a exacting way to do it, and even the orthodox like the Greeks who only keep one rite, one monastic rule, change it on occasion, it certainly does mutate era from ere, especially whenever they try to restore authentic orthodox practices, or far separated traditions presumed to be identical bump into one another and they discovered it somehow changed a bit over time. They have had schisms over the tiniest, meaningless things, like Calendars and the crook of the finger or how you do the cross, etc, wear shoes or not behind the altar. It shows how extreme the late Roman Empire took to trying to standardize practices, and it never quite worked out. In the west, we remained a little looser, given proportionally we tended to still of been converting more and more, and didn’t have a central emperor after the schism guiding practices in the church.
I do need to point out we had other sort of rules that moderns don’t think much of, like only bishops, not priests, could preach. A liturgy was highly standardized, wasn’t preaching. The authority to preach cane straight from bishops, because while giving wide allowances to ideas not of Christian origin, they didn’t want someone not of the apostolic tradition (all legitimate priests are) or not well educated or taught (not all apostolic priests unfortunately are, we do much better in modern times). You never know how the dialectic would unfold, someone might ask a priest a question, it would lead to a innocent mistake, then 50 years later a Bishop comes around, discovers the local religion mutated into something alien to Christianity. Likewise, a Bishop could choose a non-priest to preach, it could and often is a woman. They can’t be made priests, do his functions, but if you have a woman who did go to a seminary, had the same degree as a male priest, was effectively a rabbi, it is easy enough to get her permission to deliver the homily. I could do it, theoretically most of you could… but none of us would be the priest, we couldn’t take confession, we wouldn’t do funerals, etc.
You’ll find Stoic terms mentioned in the New Testament, some of the rites were assimilated out of mithraic practices, etc. These aren’t really of concern. Your asserting alien demands of purity on Christianity, when we always were a organic outgrowth of local spiritual practices merging with the Jewish Godhead. Protestant tried to purify the religion, failed miserably, still quite traceable back to pagan elements and traditions. This isn’t nearly the controversy in the ancient churches, we all kinda knew.