Though the sympathies of Democrats of all ages had tended to shift toward Palestinians over time, those aged 23-43 had the largest swing in the most recent poll and are the only group where sympathies for Palestinians now outweigh those for Israelis.
https://www.newsweek.com/democrats-joe-biden-palestine-millennials-1835455
there's an increasing divide between real people and the owner class when it comes to Israel. Our government treats Israel like it has an unlimited budget and can do no wrong because the realpolitik is such that they need a client state in the middle east. Regular, everyday people OTOH are being shown a war of genocide in real time from dozens of different angles and it turns out that watching it happen live invokes vastly different feelings than watching a press conference where Israel and the US congratulate themselves on establishing a daily 4 hour window where they won't bomb civilians unless they really, really want to. It's turning out that there actually is a number of innocent lives we're not willing to trade for one guilty life, and that for a lot of us that number is 1. It's turning out that we're smart enough to realize that evacuation warnings on twitter in english are probably aren't meant for an Arabic-speaking population that lives somewhere where the internet has been cut off and are, therefore, just Israel trying to manage its reputation in the west. We're also human enough to realize that we wouldn't accept someone firebombing our entire neighborhood to rubble even if one of our neighbors was evil and they sent an evacuation warning first, and that the basics of decency demand that we don't ask Palestinians to do so either.
The thing that sunk the Vietnam war in America was embedded journalists. People who have seen war have a hard time defending it. So the war machine adapted: now you only get access to report on the war if your reporting supports the war effort itself ("winning the war") and the effort to maintain moral authority while waging the war ("winning the hearts and minds"). Thing is, now anyone can broadcast themselves to the entire world at a moment's notice. It was already hard to limit the reporting capabilities of 5 or 6 news orgs, now everyone you're trying to have a war with is their own news org. Why do you think they tried to shut down the internet in Gaza almost immediately? Why now are they targeting a platform where anyone can go live and the data is out of the hands of western governments until after it's already in the eyes and ears of western civilians? They're trying to stem the flow of information because if we know what's going one we're not gonna support it.