because the OT is so messed up. First of all, the OT is still part of the Christian Bible, so many Christians take it just as seriously as the NT. And there is stuff in there that is not draconian, and is in fact liberating, such as the story of Moses freeing the slaves and many strong female role models that are almost entirely absent in the NT. Then there's the fact that the primary followers of the OT had their population severely decimated by that little thing called the Holocaust. And finally, those are the texts that Jesus himself drew inspiration from; if you like his teachings you cannot toss out the Hebrew teachings that informed him.

As a devout agnostic, I don't believe the Bible is inerrant, but to broadbrush the selective Jewish teachings that are included in the Christian Bible comes close to being anti-Semitic (although, knowing you, I am 100% sure that wasn't your intent).