Turkey was founded after secularists defeated Islamic Ottoman forces in the early 20th century, and many modern-day secularists frown on Ottoman symbols.
MORE: http://www.cnn.com/2013/06/18/world/europe/turkey-protests/index.html
See also...
'Standing man' inspires silent demonstration in Turkey
http://www.cnn.com/2013/06/17/world/europe/turkey-protests/index.html
