TEL AVIV — During last summer’s Gaza war, Khader Abu Seif was living with his then-Israeli boyfriend in Tel Aviv, wondering whether Hamas rockets could reach them from the coastal strip. He thought yet again of the dichotomy of his life as a gay Arab Israeli citizen considered an outcast by the Palestinian society for his sexuality and viewed with unease by some Israelis for his brand of nationality. The rockets were not the only thing that made him feel unsafe. Outside, Israeli extremists rallied on the streets against Hamas’ attacks with chants of “Death to Arabs.