By implying that voting is a moral obligation, it elevates voting higher than political activism and organization

For the layperson, I think this elevation is mandated.

He was equally alert to the problem of voter fetishism: voters mistakenly thinking the vote is an exercise of power, when in fact power in a capitalist society is collective, social and located largely outside the parliamentary realm. source

I am not a marxist or communist. I am a self-professed and proud liberal, so while I appreciate your good faith reply, I reject your source as a valid authority.

If voting is the end of political participation, the people will always lose.

Unsupported claim. But also I don’t disagree. It’s important to become involved in other ways than just voting. For example running for office at all local levels and becoming a local politician. Neglecting to do this and complaining that there are no good candidates is an exercise in lazy whining. Become the better candidate. Run on your principles.

By holding grudges against Trump voters who regret their vote, we limit our ability to effectively organize against the incoming fascism. I would gladly march alongside anyone who opposes Trump, and I hope you would too.

I don’t think people really have any excuse for being ignorant enough to vote Trump. At some point, individual responsibility comes into play. If such a person takes real action to correct the harm they have done, I may consider forgiving them. But this forgiveness will not come preemptively nor should be expected or taken for granted.

The other problem is that I don’t see these people. I have yet to meet a leftist who is truly sorry about their actions during the election. They’ve dug in on blaming everyone but themselves for the situation that they’ve put us in. Which is why in practice, I cannot forgive my grudges, because they truly are not repentant.

This is why I don’t think the dilemma is comparable:

However, in real life this is rarely how people judge how to cast their votes. Generally, Democrat and Republican voters are afraid to break rank because if the voters of one party vote 3rd party, and the voters in another part stick to party lines, this means that voters who voted 3rd party will end up with the short end of the stick. This incentivizes voters to stick to party lines and vote for candidates who are “good enough” (which represents the worst option of the prisoners dilemma in which both of the prisoners confess), reaffirming the two party system and preventing the possibility of more viable 3rd parties which can represent the views of the people better. source

Taking a thought experiment and scaling it for millions of voters is a fool’s errand. We’re dealing with social dynamics and fluid variables. I can agree that on an individual basis, or a small group, it could be a helpful tool. But, with large numbers it ceases to be viable. It fails to account for irrational prisoners that both confess, leading to the worst outcomes.