I think you don’t understand the point of view of diversity advocates. (I don’t mean this negatively, it’s often difficult to understand people who have very different perspectives)

> I have not observed anyone ever trying to intentionally underpay female or minority candidates

Most bad things that happen in our world are not intentional. Car accidents kill millions each year.

One idea you may want to consider is that salaries are often set based on what someone earned previously. Therefore one bad actor can roll through 10 or more later positions without anyone acting intentionally.

> there are lots of non-minority male nerds who spend ridiculous amounts of time... to the point that they have no social lives and may never have a family

An alternative way to parse these same facts is that white men are more likely to be in an economic condition where it is possible to spend time on non-income-generating activities. For that matter I think at least some men believe a social or family life is not something they could have achieved. In any case I think it is harder to disentangle choices from cultural forces than you think.

> I’d also like to see research that controls for things like... how many hours do they work on average?

I’d like to see research that explains why working more hours is good for society. Buried in your questions are assumptions like “equal pay is fine as long as it doesn’t change the system too much” but the diversifist assumption is “lack of equal pay is a code smell for underlying problems in the system.”

> we can’t say it’s a result of discrimination unless we’ve controlled for all the actual variables

I think here you are projecting your values onto another position. (Intentional) discrimination is the problem that would annoy you, and so therefore diversity advocates should do research to establish a problem you would care about. From the perspective of incorporating you as a political constituency I don’t think you’re wrong.

However, the actual pro-diversity position is something like “I’m annoyed that our society values traits common to X group and not traits common to Y or Z.” As a person in X group this argument is statistically unlikely to impress you, but it is harder to tease out if this is because you intentionally dislike Y (“intentional discrimination”), if there is something important we will lose if we start to prefer more Y traits (perhaps a traditional conservative type position) or if it is just hard to envision a society different than the actual one we live in.