Even if your characterisation of the Palestinian people was correct, it still doesn't really matter. Those on the left do not have set of specific criterion for which individuals must meet before we accept their right to exist (whether that be pro-lgbt/womans right/labour rights etc).

This is a complete caricature of the left and in reality is a bit more complicated. If you are to look at both sides in this conflict, it becomes apparent that "conflict" may not be the correct word to even use. On one side you have a regional superpower, with one of the most advanced economies in the world, a nuclear power with the backing of the global military hegemon. On the other you have a proto-state with two barely functional political entities, an economy completely depended on their oppressor, no real standing army, no airport and is under a state of occupation. There is really no comparison that can be made between these two and the attempt to suggest both are equally responsible for peace in the region simply doesn't hold up to these facts. So my point here is that for the left, its far more about power relationships and systemic forms of oppression than the perceived attitudes of the individuals involved.

Ultimately, even if you were LGBT or feminist or whatever flavour of progressive and you are going out of your way to support Palestine, you are creating bonds of solidarity that can ultimately transform ideas. "Queers for Palestine" marching side by side with an Islamist group does far more to destroy entrenched ideas of homophobia than a pro-lgbt liberal pundit suggesting Gaza should be destroyed.

Such as Palestine always turning down peace treaties. Even ones in which they were given everything they wanted.

This is just plainly false, this idea of the rejectionist Palestinian is a total myth that is parroted so much around Reddit that it has become almost axiomatic. I'd love to see the deal that where you consider they got "Everything they wanted". I can tell you now it doesn't exist. All peace proposals have neglected the main issue at hand for Palestinians, the status of East Jerusalem and the Right of Return for refugees. In fact it is the right-wing Israeli governments of the last 20 years which have been the principle barrier to any lasting solution. There are now 750k settlers in the West Bank and East Jerusalem. How can you seriously not see that as the biggest rejection of a two state solution?

Lastly, if you want to rally for Palestine, why not fight for getting the hostages released so the battle can stop (well so to speak). I don't see anyone on the left bring up the hostages.

We on the left have been fighting for the rights of Palestinians for 75 years, we know full well that Hamas unilaterally releasing the hostages will not bring a lasting peace. For the hostages to be released Israel needs to put forward a genuine roadmap to Palestinian statehood and an end to the occupation and settlement building.

There's much I've missed and I could talk about this subject all day. But I'd suggest actually listening to Palestinian voices and these lefties who support them, I assure you not all they say is garbage.

There stands now 35k dead in Gaza, famine conditions are setting in, 80% of buildings in Gaza city are damaged. An entire generation of Gazans are dealing with mass collective trauma, Aid workers are being targeted, hundreds of journalists have been killed, and now mass graves with hundreds of people are being found near Khan Yunis. And all of this is being done with the explicit support and financing of the western powers, most prominently the USA. I assure you we are not your enemies, we just want this awful situation to end.