The reason these posters were not just in Spanish is because there is one thing that is required for revolution: solidarity.
Revolution is not in English; revolution is not in Arabic; revolution is not in Spanish; revolution is not in French. The goal to exterminate Zionism can only be achieved with global solidarity for the greater good. Palestinians being trampled by Zionists are of equal importance as Koreans being massacred by Americans. Iraqis being massacred by Americans are of equal importance as the Irish being dominated by the British. The fight to end Zionism, Imperialism, and Globalization can only be achieved in solidarity. No human life can be valued more than another. For us Muslims, the jihad will continue to the Day of Judgement. For the Marxists, their struggle will continue until their martyrdom. Either way, the necessity for solidarity has always been obvious and effective. The language of revolution will always be solidarity.