History is replete with evidence of destroyed artifacts, churches, museums, palaces, mausoleums etc. Investigation shows that often it was those of the Muslim bent that were responsible. They destroy what they cannot comprehend. The majesty of everything that occurred after the 7th century eludes them.
According to them, history begins and ends with Mohammed. Everything prior to the 7th century is either paganism (or at best a precursor, in the case of Judaism and Christianity), everything that happened afterwards is heresy and the work of infidels. They have their Koran and neither want nor need to know anything else about the world, and to prove it, they destroy everything that's not of the Koran.
What's happened is a vacuum was created where a heavy-handed government is needed. The maniacs who previously were dealt a heavy hand filled that vacuum.
They're like the book LORD OF THE FLIES. ISIS is emotional, social, cultural, and ethical midgets who only know how to destroy the institutions that used to keep them in line. Obama was calling them the JV when we were cyber-screaming to disintegrate them when they were marching in a column into Iraq.