Trump supporters stormed the building in an attempt to obstruct Congress voting and forcibly have them change what they are doing (certify Trump instead of Biden).

It isn’t an insurrection because it was violent enough or because they were unruly enough (a bloodless coup is still a coup). It’s an insurrection because its aim was to seize power, unlawfully, in this case for the guy who lost the election. Whatever riots happened with no political goal or agenda to overthrow the government are irrelevant. However violent or unpleasant they were, they are not described as an insurrection because they aren’t and insurrection