In preparation, European Algiers had imposed on itself a total shutdown. All through the morning pied noir farmers from the Mitidja, whipped in by Martel, poured into the city. Cars raced through the streets, sounding out on their horns the now familiar tattoo of AL-GÉR-IE FRANÇAISE. The university had been thoroughly organised by Lagaillarde, and a special "commando" detailed to stand by in readiness outside the railings of the "G—G". Shortly after midday Lagaillarde appeared at the Otomatic (now recovered from its bombing of the previous year) and announced dramatically to the students there: "From now on I consider myself an insurgent." By early afternoon the Rue Michelet and its tributaries were a solid mass of demonstrators and banners, an estimated 20,000 strong (Salan says 100,000). As passions rose, a first victim—ritualistically as in almost every civil upheaval since 1945—was the American Cultural Centre, sacked by an angry detachment of pieds noirs.

QUESTION: Why did the American Cultural Centre become the ritual first target for pied noir demonstrators in 1945 onward upheavals?

Horne, Alistair, A Savage War of Peace- Alge…, loc. 867