The usual way - society.
If a person being offended is more important than someone else being offended, that person has higher status. When a person being offended is far more important than any number of other people being offended, that person has a much higher status. Since being offended is wholly subjective, the degree of priority given to it depends wholly on the relative status of the people involved.
The media/press has helped create this culture. Run to Twitter, press pays a fee for the story, coverage, all over the Internet, ratings are up, more money in ad revenue and it has gone viral. Get them all on Twitter discussing it. It becomes a TV broadcast story. Everyone is a winner.