Depends on who the dead guy is and how his image is displayed.
Many crucifixes have a tiny jesus on them, ergo, they're wearing an image of a dead guy. Jesus himself never did anything extravagantly bad.
The Mayor fully supports the freedom of everyone to wear images of Mohamned, another famous dead guy.
That some people are foolish enough to wear images of Che Gueverra, a terrorist and racist bigot, is, yes, exceptionally tacky, but those people have the freedom to be as stupid as they wish.
Would there ever be anything wrong with wearing George Washington, Thomas Jefferson, James Madison, Benjamin Franklin, Lincoln and Grant? How about the Einstein images? Should we not inspire our children to be like the famous entrepreneurs, Alexander Bell, Edison, Tesla? Should not the intrepid explorers be honored, the Columbus, the Magellan, the Lewis and Clark?