@blueveinedthrobber,
Is there a reasonably certain objective explanation of how the man was injured?
There doesn't seem to be evidence that the police deliberately targeted his head with a projectile.
Is there an argument to be made that tear gas or flash grenades are inappropriate methods for crowd dispersion? Both are categorized as non-lethal.
The man's injury is very unfortunate, irrespective of whether or not he served in the military, but was it a terrible accident, a case of negligence, or an intentional act?
When the police tell a crowd to disperse, and it refuses to do so, what is the appropriate response for the police? Obviously endlessly repeating the dispersal order will be ineffectual. How can the police allow their authority to be flaunted?
If tear gas and flash grenades are too extreme, what methodology is permissible?
Is there no point when the city can say: "Ok, time for you all to go home?"