Institutional violence is so normalized in the United States that conversations about state violence often center the groups resisting as the perpetrators of violence. This means, when the state harms its people and the people protest this harm, they are seen as the ones who ‘started it.' It's fundamentally important to understand that a protestor is a responder, not the instigator.
As to when this institutionalization started, I'd hedge a very safe bet on the beginning of the United States. Before the nation existed there was rampant racist practices and violence, absolutely. It became a legitimized, structured system when the government was formed. Governments create infrastructure and develop centralized institutions. When common practices of racism become aligned with these systems, it becomes embedded and structural.
What is institutional violence and how did it become such a prominent fixture? In Black Power: There Politics of Liberation, co-written by Kwame Ture and Charles V. Hamilton, they explain it thusly:
"When white terrorists bomb a black church and kill five black children, that is an act of individual racism, widely deplored by most segments of the society. But when in that same city five hundred black babies die each year because of the lack of power, food, shelter and medical facilities, and thousands more are destroyed and maimed physically, emotionally and intellectually because of conditions of poverty and discrimination in the black community, that is a function of institutional racism. When a black family moves into a home in a white neighborhood and is stoned, burned or routed out, they are victims of an overt act of individual racism which most people will condemn. But it is institutional racism that keeps black people locked in dilapidated slum tenements, subject to the daily prey of exploitative slumlords, merchants, loan sharks and discriminatory real estate agents. The society either pretends it does not know of this latter situation, or is in fact incapable of doing anything meaningful about it."
In the latter part of this quote, Ture and Hamilton are describing what is now known as redlining, which is acknowledged as a form of institutional violence. There is a lot of additional evidence to the state’s negligence and malevolence; from slavery being regulated by the government to the present day situations at Flint, Michigan and Standing Rock, North Dakota. If this state enacted violence wasn't a predominant narrative we would be unitedly aghast at such deplorable acts.
Instead, we have an incredibly divided nation. It always will be to a degree if we remain a democracy, but the malevolent ways in which it is fractured do not add to any discourse. Disagreeing with protests simply on the grounds that resistance to the government is inherently violent and intolerable is a dangerous authoritarian opinion. Ceding rights and liberties for a false illusion of safety causes endorsement of violences with an equally false presumption they will be exempt. Violence is a double edged sword, a wild animal. Something to always be wary of.