The map's performance was just a serious thing. A technical issue rather than a designers issue. I think you should take it as a fact instead of seeing it as a debate that has to be won. It's not a debate, it's help from another mapper that attends you on things that can be done better in your map. In this case, they have to be done in order to make the map playable for the average player.
I don't want to make war about such a thing. I'd say, just accept it as a comment and take it into account. Anyways, it's not worth a fight. If you want to discard such comments, you're free to do so.
Oh, besides, I've commented on your map again, it may contain the solution to your vis-problem. Since I have experienced a sort-alike problem a while ago, I just thought on that yesterday.