I understand you have bad blood with IPS but showing you are a better person and not saying shit like this would make you look 1 kagilllion times more mature. Saying " Jeff, thanks for your input but I feel you posting in my thread is un-helpful." is a start.
I feel for you dude, i really do. I was in a very similar situation with a site sponsor and after a few days I realized that it wasnt worth being angry over. Just move and and play it cool.