I know very little about what's in the bible, but from what I understand/know, jesus came up with two laws that trump all others.
The Golden Rule
Love thy neighbor as you love God (or something to that effect)
(oh, and render unto ceaser's what is ceaser's, render unto God God's)
I don't think they (christians) used jesus to get rid of the old laws. You have to remember, when the gospels were being written, slavery was okay. So were a lot of other things that we might just object to nowadays. So your argument that they used him to get rid of "morally defunct" laws fails due to the culture of the time.
Want to help give back to the world community? Did you know that your computer can help? Join the newest TeamEvC
Climate Modelling to help improve climate predictions for a better tomorrow.