High IQs might have deleterious side effects, but even ignoring the possibility of those ever being fixed- given the association of IQ with negative side effects, if I offered you a pill that would give you an IQ of 80, would you take it?
If we raised the intelligence of everyone future child that would have had an IQ of 80 or below to 100, would that not be an improvement to the human condition? If we eliminated genetic diseases, would that not be an improvement?
Intelligence is the red queen and an arms race, if you start raising anyone's IQ then you will have to raise everyone's IQ. If you do so genetically, then you will be genetically modifying pretty much everyone.
Since the technology and its long term implications are not understood at all, it's basically a giant experiment on the whole of human race. Not to mention other unexpected side-effects like the genomics wars from Star Trek where your enhanced people start wanting to rule the world and are cunning enough to do it. Another example if Ozymandias from the Watchmen, imagine someone with that level of intelligence wanting to fix the problems of the world... by any means necessary.
You don't know what you are getting yourself into, and optimism won't fix that. And if you go wrong you will probably have a genocide on your hands, either them the genetically enhanced killing you or you killing them.
I mean you could create a theory like the Nazis had if you were genetically enhanced people that would be scientifically true. Where does that leave the rest of humanity? No more than Jews to the Nazis. If the Nazis had given Jews a choice to join them and become Nazis by genetically engineering themselves to being the Blue Eyed Aryan race, would that have made Nazism okay?