You can't get buyer's remorse if you knew Biden was shit but felt forced into making that choice. I guarantee at least half of the habitual lesser-evilists have learned to abandon all hope and expect nothing good from their party ever again. There is only the obligation to retain a defensive posture to defeat the Republicans in a vain effort to prevent the acceleration of their immiseration, and a bitter, cynical contempt for the (typically younger, more progressive) "purity ponies" whose spirits haven't been broken yet and who dare to make demands from their captors from a position of weakness, demands which could raise people's expectations and jeopardize their purely defensive, harm-reductionist efforts.