NOTHING. The Islamic State (ISIS) and the Taliban, for many years, have been tearing down centuries-old statues and artifacts, burning books and ancient manuscripts, while blowing up buildings and symbols of pre-Islamic history.
The neo-progressive communists (BLM/SJW/Antifa) are behaving just like Islamic terrorist authoritarians. To allow people to destroy history, is to fall into the muck of fascism and mob rule. The Alt-Left and Islam are actually two sides of the same coin. No wonder they get along so well…if you remove the religious aspect and ignore the Muslim oppression of women and mass executions of homosexuals.