The oppression of Palestinian people by Israel predates the existence of Hamas. Gaza (until 2007 when the blockade began) and the West Bank have been under Israeli military occupation since 1967, against international law. Hamas is a more violent, more radical descendant from the Muslim Brotherhood and was founded in 1987.
What I don’t understand is why many reject Sharia law as fascist and undemocratic, which is a justified opinion, but hand-wave Zionism even tho it’s the same fascist Holy Scripture bullshit in a different color.