There was no Bible at all before these decisions were made. That is, it's not as if some group set out to "edit" the Bible. The Bible came into being that way.In addition religious teachings were written by persons whose own beliefs colored their interpretation of what was to be communicated. In Christianity for example, what teachings were to be included in the "official" version of the Bible and which were to be excluded was decided by a group of men. The men who made these decisions often had more that altruistic reasons for making the decisions they did. .
Prior to that, individual sects kept their own copies of scriptures, though many of them were (obviously) shared.
Please post any evidence you may have concerning "more than altruistic reasons for making the decisions"
This may have been true in the past. However, with the recovery (and translations by modern, more well informed experts) of many early pieces of the ancient scripts, along with more and more examples of the ancient script being analyzed in other contexts (non-religious,) the situation is improving.As times passed mistranslations and alterations further distorted the original concepts of the teachings
However, it is unlikely in the extreme that any original concepts were distorted by translation errors. The continued use of an old translation (like the King James Version) can cause misconceptions to arise itself. The English language in King James' day was not what it is now. I don't mean "thee" and "thou," it goes much further. An example would be "Thou shalt not kill."
Even in James' day, this was considered an admonition against murder, not merely killing. The use of the term "kill" had a more murderous undertone in those days. Yet a large majority of worshippers use the modern version of an old English word, utterly unaware they are wrong. Note that this error is not due to translation at all. It is more due to a belief that the KJV is "traditional," and the social inertia that goes along with such a mindset.