Speaking only for myself, but I’d wager this is pretty common: registered independent, but my voting pattern is consistently solid blue. Historically I mostly just don’t want to give the poll worker any reason treat me less-than-ethically due to not aligning with their party of choice. Now-a-days, I don’t want a D next to my name when the Nazis we just elected start making their lists of undesirables.
Biden could always have him [official business]ed.