This is the kind of discussion that I feel would be better to have in-person; I am not a great writer :)
Re: Israel & the term genocide, if you closely look at the combination of:
(1) the words that came/are coming out of the mouths of Israeli cabinet members, Knesset members, and the Israeli media (especially in Hebrew!)
(2) the policies enacted on the ground in Gaza and the West Bank
(3) the actions taken by the IDF in Gaza since Oct 7 (I won't enumerate them here)
(4) the clear cut plans for a "greater Israel"
(5) the extra-territorial conflicts & attacks (esp. the 12 day war and Qatar strike), and the ground invasions in Lebanon & Syria, the latter under the guise of "minority protection" (a tale as old as time)
You must conclude that Israel is at the very least committing war crimes, and is the least rational actor in the Middle East. Palestinians, their allies, and (at the nation state level) South Africa & observers took it a step further and argued that the sum of the above constitutes genocide.
> Russian decisionmakers at the highest level have repudiated the existence of Ukrainian ethnicity
What Russia is doing here - and what it did with the USSR - may constitute "cultural genocide", but this is not legally defined. Keep in mind that Israel also denies the existence of Palestinians and reduces them instead to "Arabs".
> in ways I don't think map cleanly to how the IAF has prosecuted the war in Gaza
Three questions that I find helpful when comparing the two situations generally:
1. Does Hamas have an air force or access to air defense systems? If not, does that make it easier or harder for mass killing to take place when compared to the situation in Ukraine?
2. Does Russia regularly level entire buildings - with civilians present - in exchange for so-called "high-value targets"? All AI-driven btw, giving us a glimpse into the future of warfare.
3. Does Russia control the entire border of Ukraine? And has it ever enforced a total blockade on all goods entering Ukraine?
> but there is by rights already a Palestinian state in the Levant: it's called Jordan, where Palestinians have, at multiple points over the last 50 years, made up a majority of the resident population.
It pisses off advocates because it actually ties back into how Israel erases the Palestinian national identity, and is a common hasbara talking point :)
From day 1, Jordan has been a malicious actor of sorts in opposition to the Palestinian national movement. The West Bank post-partition was supposed to be given to a Palestinian ("Arab") state, but Jordan invaded under the guise of protection, which was a valid excuse, but also an excellent opportunity to establish Transjordan. The Jordanians held control until 1967. In 1967, many Palestinians were forced to relocate to Jordan in a second Nakba (called the Naksa[1]). Soon after this, the PLO escalated its fight against the Jordanian monarchy, culminating in Black September. Today, there are a large number of self-described (very important!) Jordanian-Palestinians residing in Jordan, but they still have ties to Palestine, and claim it as their homeland even after multiple rounds of expulsion. In other words, even in Jordan, there still is a separate Palestinian national identity that lives on.
As far as the camps go in Palestine, Jordan, Lebanon, and Syria, that's a separate topic of discussion. A big part of the continued existence of these refugee camps in Arab countries throughout modern history is the optimism of Palestinians & the host Arab states that a solution will be reached soon.
> from people who correctly observe that Israeli Arab citizens, of whom there are a great many, have vastly more rights than black Africans had under apartheid
South African apartheid is the model, but not the only form. I believe that there is sufficient evidence for the argument that Israeli Arab citizens do indeed live under apartheid, mainly due to the ethno-religious nature of citizenship in Israel proper.
[1]: https://en.wikipedia.org/wiki/Naksa