Poor Sport or Bad Loser

I was playing online chess on the train commute this morning. A good game matched against an opponent only two points separating our ranking. We were into the end game and I managed to get a queen against his remaining rook. I then trapped his rook and was ready to finish him off with my queen and king to his lone king.

Rather than take his next move he offered me a draw three times. Since I had the advantage to win I declined each time. Rather than move (I would have been able to check mate in 3-4 moves) he let the time run out. I was awarded the win based on time but this seems like an approach of a poor sport.

He could have resigned or played for a stale mate draw but to offer a draw when you are behind is insulting.

Seems online games see more of that due to anonymity. Any thoughts?