Does being offended have any place on a site like Fluther?

In other words, I wouldn’t invite my friends who allergic to shellfish to a tour of New England’s greatest seafood restaurants so we could review their shellfish. Or if I did, I would expect that the friend would have to stay away from the dishes that s/he is allergic to. But what if s/he ordered what she thought was merely haddock, but it contained a sauce prepared with shrimp? Our tour and review would be derailed because we’d have a friend on the way to the hospital.

I have come across more than a handful of people who pull the “offended” card here, and I am very confused. What exactly do people mean when they say that they are “offended”? Do they feel that this quality of being offended has any place in an activity that is specifically designed to be an exchange of ideas and opinions? If “offended” simply means “I disagree”, can we agree to express this concept by stating “I disagree”, rather than the show-stopping “I’m offended”?