The concept of free speech has reasonable limits.  Yelling "fire" in a crowded theatre is one such limit.  

Another reasonable limit applies to foreign nationals seeking to whip up political dander among an expatriate population.  

Unless we want immigration to be capable of being confused with some form of aggressive invasion (which is being redefined by the moment), and thereby invite even more legitimate fears that would hinder the flow of legitimate immigration, we have to accept that foreign agitators have absolutely no right to address a gathering of their compatriots in another jurisdiction.

This is where we need a good-fences-make-good-neighbours policy.  The fact that a soaring megalomaniac like Erdogan is the instigator in this case should provide an extra alert that this is not a legitimate free speech issue.