the early Christian church could be viewed as just another regional sect. The OT is kept as part of the canonical text to show that Jesus is the fulfillment of OT prophecies, but view that the day to day requirements of being a Jew were considered null and void because of the crucifixion and resurrection became the dominant view of the early church. Sort of a PR move to increase the size of the following, because at the time there were more people in that area of the Roman Empire who were associated with the Jews and tried to follow their laws than who wanted to fully convert.
There is a lot of dispute about Paul and his influence on the early church, but I don't get the impression he hated women. From what I read he truly believed the Jesus was coming back, so marriage was irrelevant but not bad. It was later church leaders who misread a lot of his writings and promoted the view of women that can be viewed as misogynistic. Paul seems to be a more complex figure than he is usually portrayed as.
But, back to your point, from an outsiders perspective, it certainly seems that different variants of the the Christian church pick and choose which parts of the OT to apply and which to update or ignore. This situation doesn't seem like it is going to change anytime soon.