Not sure we can edit people's opinions on genetic level, or that we ever will.
If it becomes known that "some people have an opinion X, because they were genetically engineered so", people will use this to dismiss all expressions of X (even the ones coming from non-engineered people).
And if you could actually make people 3% smarter, many people would want that. Keeping it exclusively for the genetic naturists would be politically unacceptable. And if the politicians are strong enough to decides this on their own, next time there is a change in government, the same thing would be used to create smart proponents of [insert a political idea you hate].
They would be smarter at birth. Either you gene-edit your kids or you pass that up. Yes, some people would do it; and yes, you'd get genius proliferation. But so long as you've got enough hide-bound naturists, fully committed, you would always have some eco-warriors around.
There's no such thing as a million fully committed naturists, and that's why the planet is cooking and the endangered list keeps growing.
As Kurszweil is likely right, and AI is unacceptably risky; assuming we can somehow or another dodge that bullet, the problem remains of our destructive effect on Nature. Even after Climate Change has been solved; we're too good at destroying our environment. Our technology seems to be self balancing for our survival; but our effect on the planet remains a consistent problem year on year.
We need to protect, restore and preserve Nature. Lest we go with it. And IMO the best way to do that, looking realistically at humans, is to gene-edit some very intelligent people with all the genes that tends toward the naturist.
You need some guaranteed resistance to our destructiveness. If they were say, 3% smarter then the current peak of human intelligence, that should be enough to oppose and actively counteract our worst tendencies towards our environment.
Yes; you would have to accept the widespread ability to generate geniuses. But, gene-editing is coming whether we like it or not. This way, you get a committed guarantee of a proactive preservationist element.
Thousands of such people might be enough. So long as gene-editing of intelligence proves to be very difficult, a small increase in intelligence presumably wouldn't break the world.