The first widespread versions of biblical texts were published in greek, by people who probably didn't have the best grasp of the full meaning of several words in greek. The bible is so damn hard to read because it was written and translated from greek, latin, and hebraic, three VERY distinct languages with different syntax and word morphology. Its pretty acceptable to assume that the original greek version used hades because the writer thought hades just meant a general place where the unhappy dead go.
Mind you, multiple translations (translations of translations) and politics have changed the texts quite a lot through the ages, so much that only the very core of the teachings has actualy sort of survived. Pretty much every serious non-political biblical scholar, ancient or not, is against interpreting or taking bits of the bible literally.
Hell, Paul the Apostle, a once persecutor of christians, was very much against taking written words of holy texts literally, which is why he wrote his famous "For the letter kills, but the Spirit gives life" line. This was written in the context of Paul trying to convince the jews that the new testament was the natural sequel to the old testament, and that it isn't necessary for someone to partake in the judaic rituals (circumcision, eating only kosher stuff, etc) to achieve salvation, and that ultimately only faith, love and charity mattered.
Mind you, using terms and notions already known by pagans was a thing done by the early church to more easily attract converts. Paul himself tried to use the athenian notion of the "agnosto theo" (the unknown god) to try to convince the athenians that they had a notion of true god for a long time, which was now revealed through Jesus Christ. It didn't work that well at the time, but it worked rather nicely in other places.
As for an example of how politics has inserted erroneous facts into christian canon, there's the whole "peter as the head of the church" thing. The popular church enforced version of this says that Peter was appointed as head of the church by Christ himself, though there's basically no real evidence of this. They also say Peter led a full congregation of christians in Rome during Nero's time, of which there's zero actual evidence (in the letters Paul sent during the two times he was imprisoned in Rome, to christian congregations in the east, he mentions several other christians that are also in Rome, but never actualy mentions Peter, one of the apostles whom he personally knew, meaning that, if Peter was in Rome at the time, Paul somehow didn't know of it, despite keeping constant contact with the local congregation) and is also something that would basically be impracticable at the time, given that the christians were blamed for the fire that consumed most of Rome and used as a scapegoat by Nero, who persecuted them a fair bit. The only time Peter was actualy in Rome was during his execution.