I think it isn't so much when or why people are offended that is the issue (this differs depending on demographics, culture, education, religion, gender, etc), it is more so the proclivity of society more and more to censor those they don't agree with due to a perceived offense. The line is coming closer and closer to a point where anything that you say has the potential for offending someone else, and them declaring a 'right' to have your voice silenced due to that.
I think the standards are becoming vague on what is indeed offensive beyond absolution in society as a whole (abuse, physical harm, murder, torture, cruelty, racism, etc.) and that which is taken as offensive to one but is subjective to the whole (the same action or word would not be perceived as wrong or inabsolvable by another). In the latter case, a morbid joke, a prank gone wrong, a disagreement, a difference of opinion, a labeling of character or action, how one deals with confrontation, etc. The subjective examples are numerous.
