I think I'm mostly joking here, but I would like to see Vogue be more unpredictable.
You kind of have a point. I think it doesn't help to contribute to the divisiveness and to treat a gigantic part of the population as less-than. It's a good idea to start to pull them to a side that is more mainstream, less fringe-y and extreme and feed them information (after all, they're the most gullible part of the population too).
Melania has been on the cover though, not as a First Lady but surely as the wife of a prominent businessman in the US, who can say that anymore?. When she was featured on the cover, as a legitimised member of high society, wearing Dior, that was far far more Vogue, historically, than putting her on the cover as a political figure.
That said, Vogue, as a rather archaic form of media, is in a very vulnerable spot and if there's one thing more unforgiving than their readership, that is time. The country is not divided for the sake of playing black and white but for how hateful and deranged (entering Taliban ideology) the main figures on the right are (from wanting to dissolve Ivy League schools to the 'your body, my choice' guy), yes they won now but 4 years are so nothing and depending on what they're able to achieve, a democracy works in waves so who knows how progressive the administration in, say, 2032, is going to be, and Vogue will not be able to justify it. Additionally, their readership tends to have higher education, the majority of republican voters are not college-educated, so while the effort to lure them into the publication might be lucrative, will they even stay..? seems like demanding at all costs to put an icon of heavy metal on the cover when.. do their consumers listen to that?
In short, I do agree with
@blueorchid about the weird 'she's EARNED this!' argument.. but have also learned to accept that fans of Vogue do see this as the Nobel Prize of all things fashion lol, you either deserve it or don't deserve it.