This is more direct, but I always saw the original thought experiment as a way to explore that very concept - is inaction a "choice"? IMO, the only rational answer is Yes.
Even without the third rail, "no choice" is very clearly a choice. People just selfishly want to believe they don't share responsibility if they just let things happen "naturally", as of their inaction means they aren't involved. But they are. We all are. Pretending otherwise is foolish.
A thought experiment about an individual choice is not even close to applicable to the choice facing a single voter since in that thought experiment not-choosing is the same as making the default choice whilst in a vote not-chosing is leaving the choice to all other voters.
The use of this though experiment as a metaphor for the choice facing individual American voters is downright deceitful and propagandistic, self-servingly so since it's being used to try and boost the chances of one side.
People just selfishly want to believe they don’t share responsibility if they just let things happen “naturally”
Elections are a weak tool for individuals to shape policy at the national level. Observing that your Congresscritters are blind and deaf to your solicitations, that gerrymandering and voter caging renders your vote almost meaningless, and that policy - particularly foreign policy - seems to be shaped by DC mega-donors and lobbyists and think tanks more than any recently elected officials doesn't make you selfish. That's absurd.
And when you look at the miserable job guys like Eric Adams or Henry Cuellar or Richie Torres or Joe Manchin have done during their time in office, you begin to question the wisdom of this "Vote Blue No Matter Who" shit.
Yeah, that's why there's all the variations of pushing an extremely large person in front of the train to stop it, and things like that. The lever, obviously it's a choice that you should make. The person, it's still a choice, but at what point is it not an issue you should try to handle.
Voting is a lever. There's other actions that are more akin to pushing someone onto the tracks.