Confusing Draw

So, this is the end of a game I played; nevermind how idiotically, but it was a 30 min time limit, and frankly my oppenent had me on the ropes because of that.  I was black, and I had the material (I thought) to win, but I had, for real, no time.  I was down to like a second, maybe less.  I was just wildy checking his king to hold on.  White had minutes, and it was his move.  I was just waiting for the bell to ring and say, "your opponent won on time," which was fair, because he knocked me around enough that I had to use all my clock just to get standing again. But then, with just that second to go, we reached the position below, and the chess.com engine popped up the message, "game drawn due to insufficient material," which seems totally unfair to my opponent, who was just about to win.  Does this make any sense to anyone?  It looks like I had plenty of material, just no time.  Shouldn't I have just flat out lost?

This is an official rule of chess, which noone has questioned. Even if one runs out of time, the game is drawn if he material present is not sufficient for a win, even with worst play by the opponent.

Thank you so much.   I did not know that.