Not the person you replied to, but there are different narratives for it:
"Democrats didn't want it because their insurance company sponsors didn't want it."
"Democrats didn't fight for it because they needed votes from a few people who wouldn't support it."
I'm partial to the view that they could have motivated those few senators to vote for a public option if they tried. Democrats wave their hands too much on the viability of progressive policy for my taste. Whether the belief in that unviability is genuine or a smokescreen is uncertain.
It could have been passed through reconciliation IIRC. They didn't, in a bid to insulate the final bill against GOP objections to the legislation as a whole.
My recollection is that there was too much squabbling within the Democrat party to achieve it, with moderates wavering.
And with the Senate putting in a watered down public option, it killed any chance for the House to submit tgeir own.