I'm not sure I'll do it justice, but briefly, intersectionality is the viewpoint that systems of oppression affect people qualitatively differently when they're on the wrong side of two systems instead of one. From Wikipedia's lede: "An example is black feminism, which argues that the experience of being a black woman cannot be understood in terms of being black, and of being a woman, considered independently, but must include the interactions, which frequently reinforce each other."

In particular, it seems to me like the author is part of a group of people for whom certain social cues fall on dry ground, and her critics are part of a group of people for whom those social cues take root and flower like a weed. By themselves, there are advantages and disadvantages to participating in tech communities as a member of either of these communities. But they also influence how the experience of other systems of oppression affect them -- like the sexist reviewer mentioned in the article -- and it's not very helpful to think of a one-size-fits-all "feminism".

For instance, I don't think it's the author's intention and certainly not her fault if she reinforces a belief that certain behaviors are okay, simply because those behaviors don't register to her. But yet people use her as evidence that the behaviors are fine, and there ought to be room for identifying that as a problem -- not as criticism of her, but as awareness of a problem with a system. At the same time, any solution to that problem must not shut people like her out by weaving subtle social cues into the fabric of the system, or else one system of oppression is just replaced with another one.