What it really boils down to is this: "As a beneficiary of privilege, it makes me uncomfortable when people point out that racism and sexism exist. I can't say they're factually wrong, so I'll talk about the tone instead. If they would just stop being so uppity and find a way to solve the problems of racism and sexism that do not make white men uncomfortable or take any action, everything would be fine. But they haven't, and it's their fault."
Does that seem like a "concrete, non-racist criticism" to you? Sorry if I can't magically remove race as a factor in the tone argument, but reality interferes. The tone argument is made almost exclusively by whites. You can call it "racist", but you can't change the fact. Calling it racist is a cop-out, a convenient dismissal of a valid and problematic point.
For what it's worth (i.e. not much) I didn't get the same sense from jonesb6's comment that you did. It would have been nice if jonesb6 went into a little more detail about the supposed misrepresentations, but talking about misrepresentations of facts and statistics (should they actually exist) is a far cry from complaining of tone.
Finally:
> Is it ad hominem if it's true?
Definitely. Most ad hominem arguments are true -- that's not what's wrong with them.
But for the rest, the complaining about misrepresentations felt like rationalization to support the tone argument (much like making it a question rather than a statement). It's a very common pattern. My bluntness was a vent of frustration with that style of argument. If he'd wanted to make a substantial criticism, he'd have pointed to specific examples of misleading or incorrect statistics. He did not.
More to the point, quibbling about the numbers doesn't change the fundamental truths of the original article - first, that black engineers are badly underrepresented at Twitter, and second, that Twitter's attempts to address the issue have been misguided and ineffective. If the core point doesn't change, then why the quibble?
Which brings us back to tone. Which in turn brings us back to privilege.
Such as the privilege of being the majority race in the local neighborhood even if you are a minority at the national level or the privilege off being the majority of the voting population.
What bothers me the most about conversations dealing with privilege is that the louder someone talks about others, the greater their denial and downplay of their own.
That's a lot of concentration of power.
