Now I do realize that what I did in this game may be considered to be bad-sportsmanship and rude and all that jazz, but the way I see is that you play to win, and if you can't win, you play to not lose. Which is what I did.

I don't think it was unsportsmanlike at all.  When winning, one of the things you have to do is ensure the opponent can't draw the position.  Then, make sure you don't blunder away a passed pawn because you can't handle a draw that you allowed in the first place.  Way to keep your head up and your pride under control.

Great job! You did absolutely nothing wrong. He's being a sore loser because he allowed you to get back in the game.