It doesn't matter if it's inconsistent. If "lots of things" are immoral but permitted, and gene editing is also immoral, the correct conclusion is that all of them should be prevented.
If the opposite is true - that if "lots of things" are immoral but permitted, things that are equally or less immoral should also be permitted - then you're arguing for more forms of child abuse to be legalized, in the name of "consistency".
If the opposite is true - that if "lots of things" are immoral but permitted, things that are equally or less immoral should also be permitted - then you're arguing for more forms of child abuse to be legalized, in the name of "consistency".