Because the more self aware ones know it’s true, and it grates on the edge of their minds.

There are more than a few liberals who know Biden is terrible, who know that ‘vote blue no matter who’ is idiotic, but having to confront why those things are unpleasant is deeply uncomfortable. Realizing that legitimizing ‘lesser evilism’ as not just a minor harm reduction tactic but instead as the overarching aim of your supported political party is abhorrent.