Point taken on most of that. I still believe that the racial disparity in tech is a much more difficult problem than the gender disparity, because that argument doesn't change if you swap "IQ" with "SAT scores". Definitely do not want to imply racial superiority.
However,
the concepts of "black" and "white" are cultural inventions, and have no biological meaning
This kind of argument never seemed very convincing to me. It's the same you see with any kind of fuzzy data. Like what is a "species", when exactly do two groups of animals become different "species"? There's no perfect answer, and attempts at making strict biological definitions often run contrary to popular opinion. Similar to "Is Pluto a planet?", "Is a tomato a fruit?", "Is this blueish-green or greenish-blue?", etc.
The answer isn't to just completely discard the concepts of races, species, planets, fruits, colors, and many other things. It's to understand that all of those things are real scientific concepts, but their precise definitions depend on the context of use.
People get persecuted based on their (perceived) race/ethnicity. The classification of tomatoes or planetary bodies is not a life or death matter.
Additionally, the difference is that race is a product of racism, not of science. This is a historical fact. The concept of race has no scientific value. It has historical and sociological importance, though, and we should seek to understand that.
In a perfectly rational world researchers could research anything and the world would only pay attention based on the merit of the research itself. We don't live in that world. Research on race and IQ today has predictable consequences: it legitimizes racist prejudices.
If you want to stop scientists from using the word "race", at least propose an alternative. Like people who don't like that male pronouns are used for gender-neutral cases in English at least propose alternatives such the singular "they", "he/she", etc. If you think scientists need a new word for "race" because other people have poisoned it so much, your cause would probably be more successful if you actually tried to propose and promote that new word. Because scientists aren't going to just stop all research related to "race", that would be ridiculous.
"Broad cluster of people with fairly similar genes relative to other broad clusters of people" doesn't quite roll off the tongue.
Scientists already know that they have to tread very carefully if they don't want to get accused of racism. In public discourse political correctness has also made discussions about race much better. Some of the statements you've made in this thread you would never make on TV, knowing what the repercussions would be.
So from my perspective we're making good progress already, although you may not see it as such.
However,
the concepts of "black" and "white" are cultural inventions, and have no biological meaning
That's not true. If you take a look human genetic data, clusters very clearly appear which correspond with races. http://blogs.discovermagazine.com/gnxp/2013/05/why-race-as-a...
To deny that is unscientific silliness.