Casting aspersions much? The vast majority of couples I know are hetero, and not one person is like either of these caricatures. Let's not pretend sexual preference has anything to do with these stereotypes. It's more likely to be the culture or social system you are familiar with.
I think the gag is that this person reading Salon, a progressive media outlet, is a person claiming or projecting progressive values yet is dating a bigot.
Progressive dating regressive.
Among Gen Z and Millennial Americans (especially the educated straight white middle class) there's been a divergence in political affiliations between men and women. But people still couple up, so hetero couples are seeing a lot more combinations of politically engaged progressive women who are in relationships with politically apathetic men (who also tend to be somewhat sexist and racist).
My only thing I know about Salon is that at one point, they had a piece about how depressing it was to live in a hacker house, and I was like "wait. I lived in this exact apartment". I remembered the Pinterest guy who lived in the closet. That was slightly surreal.
Him being a part of every third heterosexual couple must mean he has a lot of fem presenting partners. I'm sceptical of all of them being of an ethnicity he approves of...