Palestine is an intractable situation. If you go back to analyse who did what first in order to justify tit-for-tat, you'd have to go back a very long time indeed and it's entirely futile.
The pragmatic approach is usually the best - we are where we are and things have to move forward without reference to past slights. Israel exists as a country and the Israelis will not allow it to be wiped off the map, as Hamas would like.
Opinions and weasel words my differ as to whether Hamas has dropped its covenant demand on the land currently comprising the territory of Israel, but it's by no means unequivocal. It has been declared a terrorist organisation by many countries and its military wing alone by others (including Britain).
Possession is 9/10th of the law, as we're always told, and the Israelis possess Israel. If you go against the precept of the conqueror has the right of possession, then we in the UK can legitimately contest the ownership of vast tracts of land owned by the aristocracy since William the Conqueror handed out parcels of land as rewards to his mercenary thugs.
The Israelis are defending the only patch of land on earth where they can feel safe from the next Holocaust or pogrom - anywhere else in the world - and if history has taught us anything, it's that Jews will continue to be persecuted somewhere, at some time in the future. No wonder they want to defend it.
The Palestinians have a justified beef in that their land was appropriated by an invading power; however, it can be argued that Britain fired the first shot with the Balfour Declaration. But Britain defeated the Ottomans in WWI and was therefore justified, by historic precedent, in doing whatever it wanted with that parcel of land, regardless of whether it upset others already on that land. To the victor go the spoils of war, as they say. The Ottomans themselves invaded it, after all, and before them the Egyptian Mamluks, the Mongols, the Franks, several dynasties of Muslims, the Byzantines, the Romans, the Macedonians, the Babylonians and the Egyptians.
The territory ceded to the Jews has been whittled down over the last 100 years by over 70%. Originally it was far larger than the sliver of land it now comprises. So, in a way, a 2 state solution did come about, but the Palestinians aren't happy with the status quo and want more. That, given the vast technological superiority of the Israeli armed forces, isn't possible.
Hamas has only crude, homemade rockets which don't have any targeting capability and are therefore indiscriminate. However, they have no choice in this. Israel, on the other hand, can finely pinpoint their strikes. To counter this, Hamas uses human shields and places rocket launchers in schools and hospitals, hoping to win the moral argument, but it's a double-edged sword when you put your own people in danger through rash action.
Hamas is not a democratic organisation and rules through fear, rather than free and fair elections. That denigrates Hamas in the eyes of the West. The moral argument goes against them in this case.
The blockade of Gaza is cited by many as dehumanising, as it is but, time after time, Hamas uses relaxations in the blockade to smuggle in weapons.
There is little support for the Palestinians among Arab states - they won't even allow Palestinian refugees settled status and treat them as 2nd class. Palestine is a thorn in their sides.
Israel has been censured by many for using disproportionate force, but that's how you win wars. The Allies in WWII didn't pull back from using overwhelming force when given the opportunity. It's an argument that I find specious and misplaced. Many portray Israel as the playground bully and say it's right to stand up to the bully. Others contend that Israel is more like a hornet's nest and you don't poke a hornet's nest without consequences. It's even possible to see the situation reversed, with Gaza being the annoying hornet's nest on the edge of Israel's garden.
Taking sides produces nothing productive. Any settlement has to be negotiated and brokered by a 3rd party - but even then it will be a temporary settlement and not permanent. So long as Hamas insists on the elimination of Israel, no permanent settlement is possible. So long as Israeli settlers insist on moving into Palestinian areas, no permanent settlement is possible.
If the above two canards can be addressed, then a permanent solution is possible, but it's like wanting to eliminate world hunger. So long as diametrically opposed views are entrenched, it won't happen. As I said at the start, an intractable problem that you only exacerbate by taking sides.
The radical left in the UK finds it trendy to support the Palestinians, but there again, the radical left has a habit of supporting idealistic causes that have no chance of ever happening and ignore reality. The right gravitates to order, and therefore, in general, supports Israel.
If the marchers in London were marching for peace, rather than a side, then I could agree with them, but waving Palestinian flags shows which side they've chosen.
I must admit I find it a struggle myself not to support one side or another, but I refuse to allow myself to be drawn into an unwinnable debate that ignores reality on the ground and seeks to apportion blame.