The dude on the car might not have read his criminal code lately but for the assembled masses here is a little taste:
63. (1) An unlawful assembly is an assembly of three or more persons who, with intent to carry out any common purpose, assemble in such a manner or so conduct themselves when they are assembled as to cause persons in the neighbourhood of the assembly to fear, on reasonable grounds, that they
(a) will disturb the peace tumultuously; or
(b) will by that assembly needlessly and without reasonable cause provoke other persons to disturb the peace tumultuously.
Lawful assembly becoming unlawful
(2) Persons who are lawfully assembled may become an unlawful assembly if they conduct themselves with a common purpose in a manner that would have made the assembly unlawful if they had assembled in that manner for that purpose.
64. A riot is an unlawful assembly that has begun to disturb the peace tumultuously.
Punishment of rioter
65. Every one who takes part in a riot is guilty of an indictable offence and liable to imprisonment for a term not exceeding two years.
Looks like what happened in Van yesterday might have been a riot as defined. Dude may be a rioter. Dude and many like him pissed off a great deal of folks who may want him punished to the fullest extent of the law (or to some further extent who knows) ergo - his face is on display participating in a riot.
But don't take my word for it I am just a cartoon lawyer