For the individuals who derive pleasure from robbing grave sights, they obviously have never suffered the pain of losing a loved one.
They undoubtedly have not experienced the sorrow from the loss of a child taken before his or her prime, stripped of the joy of celebrating his or her birthdays and holiday in his or her lifetime.
The individuals cannot know the sentiment of finding some kind of solace from placing ornaments on a loved ones grave on a birthday or other special occasion. Not yet, anyway. Maybe someday they will.
Until then, I sincerely hope they receive much joy and great pleasure from the beautiful decorations which adorn your yard at others expense.