Liberals, who rendered organized, disciplined, exemplary service making sure that 1/6/2021 was not worse than it was, did not like the sonics of "coup d'etat." In their opinion the term made the event and the perps sound stronger than they were. Thus, "attack," "insurrection," "riot." My fellow yellow flaggers rendered a disservice there. It was a coup d'etat, 46-1's deputy assistant on the National Security Council termed it such, European officials called it a coup, it was led by the democratically defeated incumbent who still had the levers of state power, it was aimed, with the support of other lawmakers and the assistance of some current and former military personnel and some law enforcement, to keep the defeated leader in power by violence and succeeded in preventing the peaceful, democratic transfer of power. That is a coup d'etat! 

9/11 was an "attack"; Pearl Harbor was an "attack"; Warring foreign armed forces attack each other; an attack may be the opening shot of a temporally unlimited war, or it may not be; it may be temporally limited. 1/6/2021 was from within, that is a coup. 

An insurrection is a popular uprising, this was led by the nation’s chief executive, that is a coup. 

Portland and Seattle saw "riots" in 2020, Detroit and many major cities saw riots, anti-war and pro-Civil Rights in the 1960's. A riot can be repelled or absorbed or quelled. A coup, because it occurs from within, because it is led from near or in this case at, the top, and because its aim is the state itself, is more dangerous and more difficult to defeat. This was a coup.

Why this matters: The coup has emboldened the perpetrators who, minus a couple of hundred, now see their strength that liberals denied them. Forty-one percent of all registered Republicans believe 46-1's Big Lie that he is their legitimate ruler, that his continued reign was denied him only by theft, and that the legitimate president is illegitimate. It matters because 46-1 has not gone away, he plots in the comfort of Mar a-Lago, maintaining his hold over his followers and his political party; because violent Christian fascists Marjorie Taylor Green and Lauren Boebert are still members of the Congress; because ambitious, parasitic fellow travelers Ted Cruz, Marco Rubio, Lindsey Graham, Josh Hawley, et al are still in the Senate; it matters, in short, because the threat of another coup d'etat has not diminished, it has increased.