You are correct. I've only been on this site for a few months, but I already have a "list" of those players. I even asked one player why he did it. He stated that he never gives up.....he only had his King, and zero chance of stalemate.
Kevin, just keep in mind the best revenge is to win!! Then, play others.
I have had this happened to me quite a bit recently, and it's really annoying.
If a player knows that he/she is going to lose, then that player should resign.
Letting the clock run is surely an act of imaturity, and shows that one has no sportsmanship