Watch it again. She didn't say that the United States is a corporation. She said that a corporation was formed in 1871 to deal with civil war debt.
I think she confused the Treaty of Washington with the the 1871 incorporation of the District of Columbia.
The Treaty of Washington was a treaty signed and ratified by the United Kingdom and the United States in 1871 during the first premiership of William Gladstone and the presidency of Ulysses S. Grant. It settled various disputes between the countries, including the Alabama Claims for damages to American shipping caused by British-built warships, as well as illegal fishing in Canadian waters and British civilian losses in the American Civil War. It inaugurated permanent peaceful relations between the United States and Canada, and also with the United Kingdom.[1] After the arbitrators endorsed the American position in 1872, Britain settled the matter by paying the United States $15.5 million (approximately $378.63 million in 2022), ending the dispute and leading to a treaty that restored friendly relations between Britain and the United States. That international arbitration established a precedent, and the case aroused interest in codifying public international law.
The District of Columbia Organic Act of 1871 established a new, unified government for Washington, D.C. It "incorporated" that city, a common legal term by which areas are organized for governance by a single entity. In this case, two cities and a county were merged into the District of Columbia. It made no changes in the nation as a whole and is not the basis for a restoration of Donald Trump's powers.
And the fringe on some flags is just a decoration with no other dark, sinister meaning.
Thank you for the facts!