Making the argument that because something is "natural" or appears to be similar to nature that it must be good or logical.
You should stop using medicine and instead use home remedies for healing. After all, medicine is not natural.
It is possible that the medicine is a better option in this case. Just because something is "natural" does not necessarily mean it is better.
We know that being gay is immoral because of our biology. Being straight is how nature intended us to act.
Nature intends us to act immorally as well. Many times we must go against our natural inclinations in order to behave in a civilized world.