If you choose not to decide (or vote) you still have made a choice. Biden voters who refused to vote Harris chose to let the rest of the country decide for them. They will be worse off for it. Hopefully they learn from this but I doubt it.
They weighed their experience under trump, and under Biden, and realized at worse they were the same. Trump objectively wasn’t as bad as your cult implied for a lot of Americans, and Biden was far worse than the Harris campaign acknowledged for a lot of Americans.
Between these two facts lies the failure of democrats, Harris offered nothing different, at all, during her campaign, where as Trump at least acknowledged the problems people are facing and offered different.
Perhaps people are just tired of the Democratic party deflecting blame for all their failures.
Dispose of First Past The Post voting, open the field for multiple political parties to compete to defeat the republicans. Democrats will put the country first right?