And yet everything referred to in the post you were answering - the occupation, the inhuman treatment of Palestinians etc - is factual.
There are two sides to every story, and yet most people, on most issues, end up siding with one of them. Sometimes that's because they're simple-minded and can't appraise nuance, but it doesn't have to be. It can just be because they've looked carefully at both sides and decided that one has greater weight in terms of either logical argument or their personal morality, values etc.
I support the cause of Palestinian freedom because (a) Zionism was a racist settler colonial project in the first place and (b) even if one accepts 1948 Israel as a fait accompli, there is no justification for it illegally occupying the rest of Palestine. That doesn't mean I don't acknowledge that those who swelled Israel's ranks after WW2 had experienced incredible suffering that would make anyone yearn for a safe haven, or that children born in Israel now are not responsible for the political circumstances of their parents. I just don't believe that those things justify occupying another people's land, forcing them off most of it and treating them like animals in the bit they have left.
That's my judgment and it's no more "simplistic" than that of plenty of people who look at the same facts and come down on the side of Israel. I probably know more about the history than many of them, and less than others. But at the root of this is differences of values. In particular the value often cited as the root justification of Zionism - that God bequeathed Israel to the jews so they are fulfilling His destiny - just seems completely barmy to me and not worthy of being taken remotely seriously in the 21st century.
So you don't have to be simplistically one-sided to support Hamas (which I don't). You just have to attach more importance to their position as the only political organisation in Palestine providing a resitance to the occupation, than you do to the arguments for opposing them. The most obvious reason someone would do this is because they're a Palestinian suffering under the occupation themselves, someone with - as a pp put it - "skin in the game".