The early Christians were heterodox, so it's hard to describe 'them' uniformly. It appears that for many generations in Rome and other major Roman cities (Ravenna, Alexandria, and Carthage come to mind) women held an equal status with men in the church. The earliest manuscripts describe some women as Apostles.
The slow elimination of these high-profile women from the Gospels appears to have been a gradual process, and is probably an example of incompetence rather than malevolence. By late antiquity, the Roman civilization had imploded and the sexual egalitarianism of this society was replaced with early Gothic/Vandalic/Visigothic feudalism and its male-dominated culture. Monks who grew up in this environment reading about women as equals probably just thought it was a mistake in some earlier copy and 'corrected' it.
Another cause is the accidental inclusion of a monk's editorializing in subsequent copies. An example is the passage in 1 Corinthians 14, which is now traced to the accidental inclusion of one monk's opinion, as he must have written it in the margins in his own personal copy that was later used for scribing. Subsequent monks mistook it for part of the original Gospel, and squeezed it in. Some after verse 33; others after verse 40.
Back to my earlier statement about women apostles, this was referring mostly to Junia and her husband Andronicus. It is clear in the early texts that Junia was "foremost among the apostles" (Paul, Romans 16 v7)
This was accepted for generations until the original understanding was lost, and then the mysoginist damage control set in. It followed this course:
1. Alter the wording a bit, so the 'apostles' part doesn't refer to Junia and Andronichus. From:
to:
2. Some scribes just assumed that the name was incorrectly spelled, and copied it into their versions as 'Junias'. Problem: how could two men be married?
3. Assume the passage was really about Andronicus - foremost among the apostles - and his subservient wife Junia. Rewrite accordingly.
There are other examples that show the cultural bias led to textual alterations. Paul's companion Silas in Acts 17 converted "...a large number of prominent women." Monks later changed this to "...a large number of wives of prominent men."
.) Decisions were certainly made that de-legitamised whole swathes of Christian theology, but the Canon was established later.
