Point A. Mathematically, the third party voters did not cost you the election.

But they could have in any given election. I wasn't wearing a seat belt, but I didn't crash, so it didn't affect me...this time. Well guess what? This time we crashed. It just didn't happen to be their fault...this time. This time the seat belt was voters who didn't vote.

Point B. No candidate is owed your vote.

It isn't about owing. It's about acknowleding that only two parties have the possibility of winning and adulting up and voting for the one CLOSEST to your ideals. The one whose voting history makes the most sense for whatever social/economic class you fall under. Not holding out for an impossibility or going bust with the option FURTHEST from your ideals.

The only argument you can make for the preference of the first/second party candidates is not based on merit, but popularity alone.

I guess we're living in a reality where voting history doesn't matter.