When Hillary Clinton was the nominee, she was called "Hillary” by fans, opponents, and media alike. I was told “that's because 'Clinton' means 'Bill' in people's heads," and I didn't entirely agree, but OK.

Now Kamala Harris is the presumptive nominee, and she's "Kamala,” not "Harris.” There is no other President Harris.

Trump isn't "Donald," Biden isn't "Joe,” Obama wasn't "Barack.” In 2016, it was possible that this wasn't gendered. But I can’t buy that anymore.

I don't think it's inherently sexist to call Harris "Kamala." I get that some fans will feel she's familiar, just like there exist fans of Biden who jovially call him “Joe” or fans of Obama who call him "Barack." But, in general, I think it's unduly familiar, *especially* coming from media outlets.
@waldoj I think part of it is that Biden and Trump are more distinctive that Joe and Donald, and Hilary and Kamala are more distinctive than Clinton and Harris. Barack Obama were both distinctive, so Obama was formal and Barack was familiar or condescending, It absolutely reflects the primacy of both male and Anglo names in politics, but yes, it manifests as (over)familiarity. In any sort of formal context, it’s absolutely VP Harris.
@debcha @waldoj i don't think Ronald is a common name.
Last name usage has some authority to it.
Even the army and police usually refer to the last names.