This isn't an accurate analogy. I'd say people who have this viewpoint view both parties as poison, not food. Maybe one is slightly less poisonous, but we'd rather have neither.
Its like saying: I hate getting vaccinated but I'm not gonna join take part in a society being unvaccinated. But there's only these 2 practical choices. The other ones are niche (e.g. leaving society living in a treehut or a tundra, committing suicide, going to Mars for science -- these kind of extreme outliers).
If I were American (ie. read US citizen), I'd never discount any of the dishes. After all, there's only two practical choices...
..which, despite all the current issues, makes me happy I got more than two in The Netherlands. But it also gives me compassion that Americans, given they only got two. What a system...
Abstaining doesn't get you neither, though it does increase the chance of getting whichever one you want least compared to engaging productively (and that's assuming “engaging” is just voting in the general election, and not deeper engagement beyond the last-step, lesser-of-two-weasels choice.)