I think you have it wrong. Being "flexible" isn't what they are...they're "reactionary".
For instance, if I suggested to you for years that its wrong to feed your dog human food, a flexible person wouldn't remain hard in that stance for those years. In fact, a flexible person would consider changing how he feeds his dogs, or at least decide to hear you out.
This has not been the case with the CC. The ONLY reason why they're "flexible" is because the public is pressuing them to, and not to mention, they're a big political organization as they are a religious one, and we know what lows politicans will stoop to in order to remain in or get elected to office. There is tremendous pressure to accept evolution, and the Big Bang...this much is a fact.
Look at the history of religion (Christianity in particular). They've always adjusted their beliefs to get (1) get more converts and (2), remain relevant to the intellectuals of the world.
Teachings like the eternal soul, trinity, Christmans and so on (stolen from Greek Pagans and Roman Pagans), are all beliefs adopted in their religion to garner the respect and conversion of the Greeks and Romans, repsectively.
The history is very interesting. If you look back at the beginnings of Christianity, it wasn't really "there's only one God." It was, "Hey you polytheistic peoples, here's another God, and he'll kick the asses of any of your Gods, and your ass too, if you put any of the other Gods more important than him."
The Old Testament explicitly condemns involuntary slavery and it prescribes death to those who practice it.
It issued rules for managing those who voluntarily enslaved themselves, which was the ancient world's version of the safety net. Labor for food and shelter.
You might be interested to see who first postulated the big bang theory before continuing.
Yes, I know who postulated the Big Bang theory. At the same time, let's not forget that Galileo was devoutly Roman Catholic, yet almost faced death until he recanted the heliocentric model, and was put under house arrest afterward.
As to slaves, I presume you're referring to Exodus: [FONT=trebuchet ms,arial,helvetica] "And he that stealeth [kidnaps] a man, and selleth him, or if he be found in his hand, he shall surely be put to death."[/FONT]
However,slavery was also proscribed as a punishment: [FONT=trebuchet ms,arial,helvetica]"...he should make full restitution; if he have nothing, then he shall be sold for his theft."[/FONT] (Also in Exodus)
Further, Deuteronomy says that if you go to war against a foreign land, and you see a female you want, you can take her as your slave wife.
Anyhow, [FONT=trebuchet ms,arial,helvetica]"
If thou buy an Hebrew servant, six years he shall serve: and in the seventh he shall go out free for nothing. If he came in by himself, he shall go out by himself: if he were married, then his wife shall go out with him. If his master have given him a wife, and she have born him sons or daughters; the wife and her children shall be her master's, and he shall go out by himself."
[/FONT]So, if your slave has a wife and the wife has babies, after 6 years, your slave goes free, but the wife and her children remain as your property. That doesn't sound too voluntary to me either.
And, just to go a little further, there are several places; at least 3 in Genesis as well as others, that say it's okay to rape unwed slaves - even to impregnate them against their will.