Traditionally, if a woman or ethnic minority is being harassed in their workplace, they are unable to speak out against it for fear of being fired by their bosses. In this sense, capitalist hierarchies (as the author identifies) are used to enforce gender and race hierarchies.
Now that it's become unacceptable to be outwardly racist or sexist, capitalist hierarchies are occasionally used to stop oppressive behavior. This is still rare, and not at all at the level it should be, but this is a positive trend. Just as we as a society decided that public segregation was not acceptable in the 1960s, we as a society are currently in the process of deciding that private bigotry is not acceptable.
What the author is really calling for any conflict between privileged and oppressed people to be limited to exactly those people -- which of course means the privileged person wins.
The author misses exactly the point of liberatory social struggle: to reduce the agency of privileged people, in favor of expanding the agency of oppressed people.
(As an aside, to appeal to class when discussing software engineers is laughable. I'll take the author seriously on this when he starts organizing a union for developers in his workplace.)