Peaceful protestors march all of the time without any interference by the police.
It seems you make up the "left wing authoritarianism". Here is one of many links to provide evidence otherwise:
After U.S. Park Police and National Guard troops pushed demonstrators out of Lafayette Park, President Trump walked from the White House to St. John's Church where he posed for pictures with a Bible.
www.npr.org
From the Link:
Editor's note: The Interior Department's inspector general released a report in June 2021 that concludes that the clearing of Lafayette Square of protesters on June 1, 2020, had been previously planned by the U.S. Park Police before President Trump made his public statement at a nearby church. The report is not comprehensive in that it focuses on U.S. Park Police conduct but not other law enforcement agencies and is the first of several expected examinations of the events of that day by the Interior Department. We have added our coverage on this page.
The plaza between St. John's Church and Lafayette Park was full of people nonviolently protesting police brutality late Monday afternoon when U.S. Park Police and National Guard troops, with the use of tear gas, suddenly started pushing them away for no apparent reason.
And then it became clear.
President Trump wanted to walk from the White House through the park to the Episcopal church. Camera crews scrambled to keep up with him as he strode through the park, followed by his daughter Ivanka and her husband, Jared Kushner, along with Attorney General William Barr and other administration officials.
Protesters and police clash near Lafayette Park late Monday in downtown Washington, D.C.
Tyrone Turner/WAMU
Trump stopped briefly outside the church and held up a Bible.
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"We have the greatest country in the world," he said. "Keep it nice and safe."
The visit came just after Trump delivered remarks at the White House, declaring himself "your president of law and order" and demanding that governors deploy National Guard units and "dominate the streets."