Ironically, that was one of the biggest campaign points and voter sentiment on which people flipped to Red. We all know what happened.
It was unambiguously clear that no matter how bad you felt Obama/Biden/Harris were on Israel, Trump was/would be worse.
If every single human life is worth saving (and it is), it's indisputable that Trump is worse for Gaza than Harris would have been.
It was the ultimate Trolley Problem, and a bunch of progressives acted like pulling the switch on move the trolley is NEVER acceptable regardless of how many lives it saves...
https://www.brookings.edu/articles/support-for-israel-contin...
Like a political partys job is to get votes. An electorates job is to withhold votes to punish poor performance. The entity not doing their job here is the party.
The party is aware of the trade-offs. It goes ahead with its best estimation of what will win. Sometimes they can do everything right and still lose. One such scenario is when people would rather have the greater of two evils rather than be responsible for the lesser.
"We can't adopt [potentially winning strategy] because it might harm [definitely non-winning strategy]" is not a reasonable position. You don't have to adopt any specific alternative plan, but clinging to a non-working plan clearly isn't the right answer.