I think you are not obligated to acept a draw. Your oponent needs to learn how to behave.
After he started calling you names, I think you should have click the disable chat option.
And as you say, there is some positions where the draw is theorical, like both of you agree there is no move for any one, or in cases when you 2 agree to draw for whaever reason. But if you don't want to, you don't have to.
That is my opinion.
In a recent game, I exchanged some chat with a fellow who felt I was in "bad Manner" by not excepting his repeated requests for a draw. The event leading up to this was a move on his part (he said was a mouse qlitch) in which he put his bishop in jepordy. His defense was a pawn that I had pinned. I feel he did not take into account of this, and I took his bishop with mine. In a couple more moves, I had him set up for a check mate (providing I did not mess up before hand.) At this point he requested a draw, then proceeded to call me a "Scrub" for not excepting this.
I understand that mouse glitches do occur, I have done them myself, but I have played on sometimes wining, most of the time not. I did not except his draw, as he still had a viable game to play, and one bad move did not deserve an end to a game. To me this is like pushing the pieces off the board when it is not going your way, and demanding a re-match.
I explained my position, and advised him if he wished to end the game, he should resign. He continued to badger me, calling me names, and carring on like a baby. My question is however, was I in bad form, and when is it appropreate to request a draw?
I have a few of these, some of which I requested, some which my opponent requested, that were excepted. This was due to an unforseen need to leave the game, or where the game really was just going to have no end.
Was I in bad form?
What is a scrub?