This flag represents the Vietnam War
The war was fought over whether or not the Republic of Vietnam had a right to exist as a nation.
The yellow flag with three red stripes is the national flag of the Republic of Vietnam, commonly known as South Vietnam, and descriptively known as the Saigon military dictatorship.
The Saigon regime was brought into existence specifically to fight a war against the Vietnamese on behalf of the Americans, and it ceased to exist when it lost the war. The regime and its flag are unequivocally partisan symbols of the Vietnam war.
Calling the flag by a different name does not change what it is. The flag is only flown in Canada by the former leaders and military of the regime, and their core supporters and families -- a small number of people.
Canadian politicians who acknowledge this flag are making a political statement acknowledging the right of the Saigon military regime to exist and re-framing the nature of the Vietnam War to suit their western ideology. If they do not say that personally, it is said for them in bill S-219, which is the basis for Canada's recognition of the flag.
Canadian politicians who call this flag "the flag of the Vietnamese Canadian community" are practicing identity politics in its worst form - stereotyping an entire ethnic community in the image of one of its (small) political factions.
Canada's original response to events in Vietnam is described in Canada's SE Asia policy and Canada responds to the fall of Saigon
The flag raising ceremony
Canada formally recognizes the flag as a national flag.
The flag raising ceremony is a clear and obvious signal that Canada is recognizing the Saigon regime as a legitimate and on-going nation (as declared in S-219). But whose nation is it?
With the on-going business around the certificates and plaques[1] that usually accompanies the flag raising, the government confirms that the Saigon regime, and in particular its military leaders, are recognized as the legitimate national leaders of all Vietnamese in Canada.
Senator Ngo puts into words when he describes the flag raising ceremony thus:
"the Vietnamese Heritage and Freedom flag was once again hoisted in solemn commemoration of the modern beginnings of Canada’s Vietnamese community".
(Ngo, 2018).[349]
The yellow scarf with three red stripes
The scarf is obviously a representation of the flag. It is a particularly cynical and hostile symbol.
During the Vietnam War, the groups that were opposed to Saigon regime formed a unified front, and as an identifying symbol they chose a checkered scarf. The scarf became very well known. The national liberation front was a coalition of both communist and non-communist groups, united in opposition to the Saigon regime.
Echoing that tradition, the former Saigon military leaders have adopted a scarf, based on their national flag, as a symbol. They encourage Canadian politicians to wear it with them as a symbol of a unified front against the enemy in Canada.
In this case the enemy is the few hundred thousand Canadian of Vietnamese origin who refuse to acknowledge the leadership of the former military leaders in Canada and identify with the yellow flag.