It ain't even in the same ball park to compare the two because although we (scientists) may be limited in our ability to assess an individual or population's (term scientists use, since 'race' is largely ill defined) intellectual ability, that doesn't change the fact that attempts to evaluate this, in any standardized way, demonstrates a disparity between groups that loosely correlates to what most would identify as as race. No one I'm aware of is saying that this disparity proves that certain populations are inherently more or less intelligent than others. But there is demonstrable evidence that these gaps in average ability between groups do exist.
Now flip that to a 9/11 Truther, or Alex Jones who claims that the Bush administration orchestrated maybe the biggest American tragedy of all time... a claim which has absolutely ZERO evidence and further, contradicts existing evidence regarding who was actually responsible.
This is what I mean when I say I think people are being dishonest. The claim sounds reasonable because it is reasonable. Literally every attribute about a person is influenced in some way by their DNA... by their genetics. Again, to my understanding, neither Murray nor Harris claims that intelligence is 100% genetic... in fact I believe both would say we don't know the percentage... but to say it's on the same level of delusion as a 9/11 conspiracy is so insanely uncharitable that it strikes me as a total bad faith comparison.