The idea that one particular party is owed my alliance no matter what atrocities they support is fundamentally authoritarian which in-itself is a principle I do not abide by.
Given your logic, all is permissible so long as we have one party we can point to and say "they're worse". Which is what leads to as situations where both parties continually move away from the interest of the people. I have far more respect for people who deny there is a genocide, as opposed to those that see it and actively choose to ignore it.
Also what is "would be"? Harris and Biden have been presiding over and supporting the current genocide. I have a hard time imagining it being truly worse during a Trump administration. At the very least mainstream Democrats can allow themselves to oppose genocide now that it no longer interferes with the aims of their party.
It continues to boggle my mind that liberal Democratic will endorse and support genocide without a moment's hesitation or reflection.
Trump's encouragement to 'let Israel finish the job' seems worse.
In a way it's like a significant number of Americans feel the same way. The people who elected Trump, then Biden, then Trump again.