Who are the Irgon and Haganah, and what was their role in the creation of the state of israel?

Arabs often refer to those two extremist Jewish organizations (Irgon and Haganah) who basically started the Jewish state in 1948. According to Arabs, those two organizations are the ones who started the state of israel by macring and terrorizing the Palestinians out of their lands and expelling them by the millions in order to repopulate their land with Jews which were brought from all over the world. Why don't we hear about those two organizations anymore, are they extinct?