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).