I won't address everything that Miss Slick said. It is very sad to see a beautiful young woman departing from the faith, regardless of the reasons, because it means that she is giving up the world to come for the empty and fleeting pleasures of this world - demonstrating a lack of lasting spiritual beauty beneath the veneer, which will soon fade.
Let me address one point she made. She stated:
This changed one day during a conversation with my friend Alex. I had a habit of bouncing theological questions off him, and one particular day, I asked him this: If God was absolutely moral, because morality was absolute, and if the nature of “right” and “wrong” surpassed space, time, and existence, and if it was as much a fundamental property of reality as math, then why were some things a sin in the Old Testament but not a sin in the New Testament?The answer to the question is that some things are wrong because they contradict the nature of God, and some things are wrong simply because God has commanded otherwise. An obvious example is the tree of the knowledge of good and evil - one tree in the garden. Is eating fruit something in itself evil? No. Rather, it was evil because God had forbidden Adam to eat of the fruit of the tree.
Alex had no answer — and I realized I didn’t either.
The same kinds of things apply to, for example, the ceremonial law. Eating bacon-wrapped shrimp was not wrong absolutely, but only because God had commanded the Israelites to abstain from such food.
It's the classic distinction between things "malum in se" (evil in themselves - like murder or theft) or "malum prohibitum" (evil because prohibited - like driving after curfew). I'm very surprised that neither Rachel nor Alex had that answer.
Moreover, this distinction should be obvious from the law itself. To disobey God (in general) is clearly a contradiction of the nature of God. Thus, it is also wrong to disobey particular commands of God, even if those commands have an only temporary purpose. To make the matter easier to follow, consider the case of the command that we obey our parents. This command may have its root in the nature of God, but the particular commands of our parents may not. There is no eternal "eat your spaghetti" aspect of God's character, yet it is sinful for a child to disobey his parents' command to eat his spaghetti, because he is not obeying his parents.
I don't believe that this particular issue is really the reason that Rachel abandoned God's law. Still, I would like to take this opportunity to help her see that her abandonment of God's law was irrational. Perhaps God will use this to draw her back to the faith - or to the faith for the first time, if she never believed.