What do you mean "How come?" ?? I disabled it because of the above reasons. Yeah it needs a little optimization, I'll get round to it one day. I can live with how it is at the moment.

It's not as bad as it looks, I had a few adverts on my site last night, which I have now removed because the cpm calculations were horrible and not worth my time.
Just after removing the ad's my site has become a lot better - and that's without me actually doing anything to the script.

GTMetrix