I totally agree that some posters are quick to name call over a difference of opinion. Which I feel is completely counterproductive. Where you are spinning the ad issue is when you say " A small number of people, who are unaccustomed to seeing nudity on a political website have asked the owner of this site to consider removing the ad. This is no different than asking the owner of a bar to consider changing the channel on the bar TV" This is not totally true. If it were, the owner of the website would have been contacted privately, not on a discussion forum board; thereby inviting responses.
A forum is not a monologue, it is a discussion arena. You may want to consider some of your own advise in your post, " Tolerance means that you accept that people are going to have differences of opinion, and different sensibilities". Personally, I never noticed any nudity in the ad until you brought it to my attention. It doesn't bother me, but I support your right
to ask the owner to change it if you feel its that important to you. However if you choose to gather support for your postion by posting your opinion in a discussion forum, be prepared to get differences of opinion as well.