It's about "identity." For someone like me, the concept consists of bits like favorite ice cream flavor, what kinds of pets does someone like, how they respond to various holidays, how they might feel at a party with unfamiliar people, how they felt the first time they struck an animal while driving, when and what kinds of tips do they leave when nobody is looking ... character is who you are in the dark, and I am interested in the little things that distinguish people from one another.
For others, identity has been deconstructed into a series of theoretically independent (believe it or else) variables where each option is totally okay. Gender, sexual orientation, racial or ethnic background, physical disabilities, mental "challenges," and so on, along the axes of oppression. That's how people divide out for that bunch of folks and apparently, you had better play along. The "I know you don't like to ask questions" bit is bleakly ironic.
addressing your specific point (and note: ignoring the submitted article): I think everyone wants to think of themselves the way you want to define identity. It's a great model and I think of myself that way too.
However not everyone has the opportunity to be thought of that way by others. When you say "axis of oppression" well, that's a loaded term for an odious situation, but that odious situation really exists. Who you may choose to sleep with is none of my business unless 1 - one of us wants to go out with the other or 2 - you are a friend/colleague and get married or have some other life event for which I can be glad for you. That's not how the world actually works, so calligraphies attention to it helps those of us who are not (say) gay appreciate the difficulty others have and try not to make things worse (at least that's the hope).
The existence of oppression doesn't make you some sort of oppressor, but don't you want to have sympathy for your fellow humans? We are all at a disadvantage some of the time.
I"ve literally been on both sides: I was born in a country where I was legally of the wrong hereditary background. When I came to the US I was magically received as "a white guy". That's great: I get to define myself by ice cream preferences etc and I see nothing wrong with that. I notice I get a pass for certain screw ups and am taken more seriously than, say, my far more educated girlfriend. Do I wring my hands over it? Certainly not! But I do recognise that not everyone gets the same chance.
I register on more than one of those axes. You likely did not consider that, or if it did, you didn't factor in.
It isn't about sympathy, it is about looking at a person as more than the just the fill-in-the-blanks set of labels. People aren't just some combination of tick marks in the privileged-or-not checklist. Saying that someone who who chooses to view the world as more than that necessarily lacks sympathy is ... kind of crappy.
And yet here we see people (in the article, which is what we are discussing) reduced to just "homos" or "Brown people." People are more than that.
For others, identity has been deconstructed into a series of theoretically independent (believe it or else) variables where each option is totally okay. Gender, sexual orientation, racial or ethnic background, physical disabilities, mental "challenges," and so on, along the axes of oppression. That's how people divide out for that bunch of folks and apparently, you had better play along. The "I know you don't like to ask questions" bit is bleakly ironic.