OK, it was written very misleadingly. Further, the comparison doesn't even make sense. RNA molecules can fold into ribozymes and carry out activity. In principle, you could make a turing machine with RNA molecules, although the error correciton would be fantastically hard.
Computer scientists, please stop making CS/biology analogies.
When someone says "A is to B as X is to Y", you're not supposed to start comparing B to X. Your post is comparing B to X.
Let me try to come up with another example... Let's say I make an analogy like "a house relates to a wall the same way a forest relates to a tree". (It's not a very good analogy, but that doesn't matter here.) If you look at that analogy and then start talking about how you can use a tree to build a wall, you are doing analogies wrong. The items on the left of the analogy are not supposed to be compared to the items on the right of the analogy. You're only supposed to compare the relation on the left to the relation on the right. Your discussion of RNA-based Turing machines is doing analogies wrong in the same manner. Turing machines are on one side of the analogy and RNA is on the opposite side.
Computer scientists, please stop making CS/biology analogies.