The alternative to harm reduction is... harm increase? Democrats being terrible and Republicans being substantially worse are not mutually exclusive facts. The election is FPTP, lesser evil is always the only rational choice.

Absolutely do everything in your power to facilitate tasteful alternatives between elections, but on election day anything other than voting for the lesser evil is tacit approval of the greater evil. Yeah, it's a shitty hostage situation, but the alternative is "Fuck the hostages".