Any commands and such in the New Testament supercede any contradictory ones in the Old. And each Testament frequently condradicts itself because it was written by a zillion different authors over probably a significant span of time. Furthermore, many of those contradictory quotes are certainly instances of different contexts, and diminish the overall strength of that argument against the Bible. Finally, the Catholic Church left the contradictions in when it assembled the Canon probably because it just didn't want to edit the "Word" for consistency (after all, it was all inspired by God, how could it be contradictory?) and/or because it wanted to have a Biblical quote to back up every piece of doctrine, even contradictory ones (usually at different times). Even given that, I, for one, disagree even with what's would be in a Dogma-friendly edit of the Bible. Which is to say that I disagree with the Church.
As for the vegetarianism quote, that goes to show that even the New Testament is faulty, and that God, if IT exists, disagrees with some of it. And I imagine you can find veg-friendly quotes in the NT. I know you can in the Old.