Despite my best instincts, I'll bite... When did Biden "promise support for genocide"?
Biden is not in any way responsible for the October 7th terror attacks and war crimes (targeted killing of civilians, sexual violence and kidnapping, to name a few) that started this whole mess, Hamas (who are the ruling party of Gaza and have been for over a decade) are.
Biden is also no in any way responsible for the Israeli response, nor is he in any control of the tactics used by the IDF in achieving their goals. Like every US President, real or imaginary, Biden will continue to support Israel because they are (a) our closest ally in the region (b) a home to many US citizens and a cultural site to many US jews, christians and muslims and (c) under constant threat of attack from every angle by enemies who in some cases have vowed to "wipe Israel of the map" (to name a few, Palestine, Lebanon, Jordan, Syria and Iran).
Despite what lemmy-think might have one believe, neither the UN, the ICJ, or any reputable organization have been able to show evidence that escalates what we're seeing in Gaza to any kind of war crime, let alone "genocide". There are 2 million people living in Gaza, and if Israel's goal was genocide we'd be seeing a lot more death and destruction than we are today. (Help elect Trump and I guess we might get a closer look at it.)
The Biden administration has been much more effective at delivering aid (by air and now by sea) to Gazans than the UN, Hamas or anyone else.
Biden doesn't want to see innocent civilians killed, be they Israeli Jews or Palestinian Arabs. Why would he?
Unlike Netanyahu and Hamas, Biden gains literally zero political benefit from the war. His life and his job would objectively be much easier if there was peace in the middle east. You know that as well as I do. In fact, I'd say it's plainly obvious to anyone with half a brain. This war is a drain and a distraction from the US's resources ability to defend Ukraine from Russia, it makes the region (and thus, the world) less safe, and it is nothing but a political vulnerability to Biden. And still, there is not a serious politician in this country that would even consider removing support of Israel in the wake of the October 7th attacks, especially given a hostage crisis that is now entering its 6th fucking month.
In other words, while you're entitled to your subjective opinion that what's happening in Gaza amounts to a genocide or other war crimes, you can't seriously blame Biden for any of it.
If you're looking for someone to blame here, look no further than Netanyahu's government and Hamas--two entities that have repeatedly propped each other up as boogeymen in order to push their communities into the political fringe for the sake of power. Netanyahu literally funded and boosted Hamas, and Hamas has done everything to maximize civilian casualties (also a war crime, btw) on both sides of the conflict.
There have now been multiple reasonable ceasefire negotiations that the Biden administration has helped negotiate which Hamas has unilaterally rejected. The world is only waiting for Hamas to do what they should have done months ago: return the hostages, lay down their weapons, and turn over the war criminals and terrorists who made it their mission to rape, kill and pillage Israel on October 7th. The ball in unquestionably in their court, and it has been for months.