Yuval Or, whose son Dror was abducted to Gaza, shouted and chased away a Religious Zionist MK who had come to offer support to the hostages' families.
Groups like Brothers in Arms and Peace Now accused Prime Minister Benjamin Netanyahu of endangering national security with the appointment.
"We are coming to protest the injustice that has been done and demand Yehiel's immediate release," right-wing protest organizers said.