I agree with you on most of your points - the author's unreasonable expectations are clearly the root of her dissatisfaction, even though there are some real problems sometimes. However there is one thing which in my observation works out differently, and that is how our "work" selves are separated form our "life" selves.
"I do not have to like you. I do not have to be your friend. I do not have to embrace your values, or way of life, or anything about you in a non professional manner. I am in my full rights to keep a strictly professional relationship with you, regardless of your race and gender."
You don't have to. But what happens if someone is being kept a "strictly professional relationship with" by everyone - they are severely impeded in their career. HR evaluates everyone's ability to get along with the rest of the team, and that universally includes your capability to find informal ties with the team. If you're the odd guy/gal on the project, that means you WILL be passed over for worse performers because of their perceived "soft skills". Put it simply, people that easily make friends with everyone on the job will get much further (well, duh). So, if you are different from the rest, you WILL have problems getting along, and you are at a disadvantage. And race/gender obviously is a huge factor factor here.
There is a self-perpetuating problem: there is a white (and to a degree asian) male majority in the field, and others have a hard time blending in, so the latter will be passed over. I don't have any good ideas how to change this, as long as "soft skills" is a larger factor with HR than actual merit.