1. Erdogan conduct in Turkey is similar to a dictatorial thug in control who cracked down on Turkish media and dissenters.
2. Video and still images demonstrates that his bodyguards were aggressors if not the instigators of the melee.
While it is plausible that there might have been one opportunistic protester that tossed a bottle or something similar and sparked the melee it seems more likely that Erdogan's men, if not Erdogan himself ordering it, did not respond well to Americans exercising their First Amendment rights.  This is also true of Erdogan's subversion of American justice, ie. innocent until proven guilty.  He seems to act that people are guilty just because he says they are.