I wouldn't say insulting but amusing. Delta has been fairly good to me as FO (do not fly many non-CRJ-100/200 routes) with free checked bags and a small bonus in miles, but I would say if they are going to send an "exclusive offer" send one that is not available 24/7 on their website. The amusing part is much of the general public will bite on it not knowing. FT and self-education are great things