The Fasces is a really good symbol for fascism: an implement that appears equal parts tool and weapon but is ultimately ceremonial, a flimsy looking clumsy approximation of utility and power
So funny story, the Fasces was apparently used as the symbol of the Consul during the Roman republic, but became much more associated with the Empire, when the Empire reached the territorial heights. It became the symbol of Mussolini and his party because Mussolini liked to pretend that Italy was about to become a great power and conquer the rest of Europe like Rome did during antiqueity, and to that end he used the classical roman symbol of the Fasces, which was meant to denote strength through unity.
The main reason it's seen everywhere in the US, is because the US (up until like 2002) liked using Roman imperial iconography, until Bush made everyone a rabid jingoist that just put flags everywhere.