Actually that happens a lot. Can't seem to drive 5 miles in some areas without seeing flowers and crosses beside the road or those white bikes in cities. And people do break down and cry on street corners for people they knew and congregate with others that knew them.
All the people morning a celebrity did know a part of that celebrity even if they never met that person. And really we never know all of a person so we all only know parts of people.
It really comes off more like jealousy. "celebrities shouldn't be normed more than normal people" But if that's true then "popular people shouldn't be mourned more than unpopular people" but then "people with homes and families shouldn't be mourned more than people who have neither" The amount of people morning will directly relate to how many knew you and if you are a celebrity then lots of people know you, again even if it's just a part of you, and why shouldn't they mourn the lost of that part they loved and did know?
I do think the media tends to go over board but they always do.