Although I find it not very polite to repeatedly offer a draw, I do not really care about it. My idea is that as long as I don't bother about it it will not frustrate me. Childish behaviour should never be encouraged, just ignored (calm).
The same applies to people who continue to play in a lost position. Sometimes I ask them, politely, if they would consider to not play until the inevitable. But if they want to play the game to the very end I respect this. I am no chesswizard, so I do not think that I should comment about how someone else sees the game. Perhaps the opponent just sees better moves than I do, or at the very least he (or she) sees moves that I do not. If someone is hoping for a stalemate, then it is up to me not to let the game finish in that manner.
In the end I think we should all try to play for fun and complaining about the opponent is not going to be very helpful in that process.