Netanyahu's political party, the Likud, were partially founded by members of Lehi. Including the first Likud Prime Minister.
Lehi was a Zionist Terrorist organization in Mandatory Palestine. Their main operations were political assassinations of any leader who supported the British, or opposed their ideal of a Jewish ethno-state. This included Jewish and Palestinian leaders.
But the meat of this tangent is what they did during WW2. See, they really hated the British. So much so that they made multiple overtures to join WW2 on the side of the Nazis. They kept trying to join in until 1942. (and only stopped when the founder of Lehi died)
According to Yaacov Shavit, professor at the Department of Jewish History, Tel Aviv University, articles in Lehi publications contained references to a Jewish "master race", contrasting the Jews with Arabs who were seen as a "nation of slaves".[47] Sasha Polakow-Suransky writes that "Lehi was also unabashedly racist towards Arabs. Their publications described Jews as a master race and Arabs as a slave race." Lehi advocated mass expulsion of all Arabs from Palestine and Transjordan,[48] or even their physical annihilation.[49]
Netanyahu's early political career was directly mentored by former members of Lehi. It's why he sabotaged the peace talks in the 90s.