Heavy-handed, biased moderating, or something else?
You state that the initial question use entitled: Why has Christianity accepted the idea that God took on a human nature when If "God is spirit" then how can the Bible only says God has a divine nature.
In fact the original question was worded as follows: Why has Christendom accepted the idea that God took on a human nature when the Bible only says God has a divine nature?
To be fair and charitable to all the facts should be presented as close as possible to the truth so that we see what we are dealing with and not some less supported argument.
For what it is worth, the term Christendom would strongly infer a response based on Christians who upheld Nicene theology. The editing out of the term Christendom was unfortunate, but it was not done by a moderator, but by another user, who did so in good faith.
The Anglo-Saxon term crīstendōm appears to have been invented in the 9th century by a scribe somewhere in southern England, possibly at the court of king Alfred the Great of Wessex. The scribe was translating Paulus Orosius' book History Against the Pagans (c. 416) and in need for a term to express the concept of the universal culture focused on Jesus Christ. It had the sense now taken by Christianity (as is still the case with the cognate Dutch christendom, where it denotes mostly the religion itself, just like the German Christentum.
The current sense of the word of "lands where Christianity is the dominant religion" emerged in Late Middle English (by c. 1400).
Rise of Christendom
Early Christianity spread in the Greek/Roman world and beyond as a 1st-century Jewish sect, which historians refer to as Jewish Christianity. It may be divided into two distinct phases: the apostolic period, when the first apostles were alive and organizing the Church, and the post-apostolic period, when an early episcopal structure developed, whereby bishoprics were governed by bishops (overseers).
The post-apostolic period concerns the time roughly after the death of the apostles when bishops emerged as overseers of urban Christian populations. The earliest recorded use of the terms Christianity (Greek Χριστιανισμός) and catholic (Greek καθολικός), dates to this period, the 2nd century, attributed to Ignatius of Antioch c. 107. Early Christendom would close at the end of imperial persecution of Christians after the ascension of Constantine the Great and the Edict of Milan in AD 313 and the First Council of Nicaea in 325.
According to Malcolm Muggeridge (1980), Christ founded Christianity, but Constantine founded Christendom. Canadian theology professor Douglas John Hall dates the 'inauguration of Christendom' to the 4th century, with Constantine playing the primary role (so much so that he equates Christendom with "Constantinianism") and Theodosius I (Edict of Thessalonica, 380) and Justinian I[a] secondary roles.
If an OP desires to equate Christendom to something other than Nicene theology, it would be better to explicitly use a definition of Christendom compatible to the OP’s intentions and thus avoid arguments.