Im sorry thats a bad argument the New testament gives us permission to stop those things however it does not give us the right to ignore the moral law. Remeber the Counsel in the New Testament?
Its true there are alot of interpretations, and id be the first to let things like homosexuality slide, however Paul is very very unforgiving on sexual immorality not limited to homosexuality.
So, as part of following that moral law, you drag your mouthy teenagers before the city council and stone them to death right? Or was that part of the old code thrown out by Jesus?
And as part of following that moral law you don't beat your slaves so hard that they die right away, but linger for several days, right? Or was that part thrown out too? Or did society evolve away from the need to follow the moral code endorsing things now considered to be, dare I say it, immoral. Or do you consider slavery to be an acceptable social construct? If you don't consider slavery (the bible not only condones this evil, it goes so far as to set up rules and regulations regarding this evil practice) to be acceptable, how can you accept any of the rules presented by the bible as applicable, because after all, the bible is the standard for setting morality. Rejecting some of the biblical code regarding moral practice invalidates your basis. Or you could just admit that you are cherry picking the verses you think should apply selectively to other people but not yourself.