The adverse effects quite possibly are that significant in the context of the ancestral environment, but probably not in the context of the modern world.

You need to develop that a bit more. It is important for the benefit of the reader and thinking in general to precisely and clearly separate genetic fitness and general well being in addition to pointing out the environment has changed.

I suggest people read up on Algernon's Law and its loopholes. In short:

Any simple major enhancement to human intelligence is a net evolutionary disadvantage.

Bostrom's formulation, called “evolutionary optimality challenge” (EOC):

If the proposed intervention would result in an enhancement, why have we not already evolved to be that way?

The loopholes as given by Bostrom are:

• Changed tradeoffs, because our envrionment has changed. What you said.
• Value discordance, between what we'd like to optimize and what evolution is optimizing for. What I said.
• Evolutionary restrictions, which don't apply to us. "We have access to various tools, materials, and techniques that were unavailable to evolution. Even if our engineering talent is far inferior to evolution’s, we may nevertheless be able to achieve certain things that stumped evolution, thanks to these novel aids.”"

And also in the current context of discussion (possibility of genetic differences between groups), if one accepts that say Askenazi Jews have a one stdv or half a stdv advantage over some populations due to genetic causes, looking at them today, they don't seem to have shorter or less happy lives or be undesirable people, so why not share that specific genetic wealth around? It has the neat side effect of basically rooting out one of the causes of anti-Semitism too, by reducing inequality, so it is hard to say it would hurt their interest as individuals or an ethnicity either.

Actually one doesn't need to demand genetic differences between groups for the argument that what we're seeing here probably fits either the first or the second loopholes, since we also have individual differences that are caused by genetics. We see that people with an IQ of 115 overall seem to statistically speaking today do better in nearly every measure of quality of life and many measures of psychological well being compared to people with an IQ of 85, they also live longer and are generally more desirable to have around.