I don't see how you're having trouble understanding that anti-genocide rhetoric can also come from the left. I would actually wager that the majority of genuine critiques surrounding the Biden administration's support of genocide would not be from Republicans, since most of those fascists love the idea of killing natives in the name of forming a white ethnostate.
I doubt there are many Trump supporters who want to eliminate the existence of trans/minorities while also saying "FREE PALESTINE" on random lemmy posts lmfao.
I guess you could take the position that they're not genuine critiques, that every critique of Biden is a false flag Trump supporter or direct KGB agent from Russia, because who in their right mind would actually give a fuck about a genocide happening to others. They're not American, so fuck them right?
If that last paragraph resonates with you, then I'd ask you to consider who in this conversation is actually the close-minded bigot. If it doesn't, then you have to recognize that there are genuine, valid critiques of Biden coming from the left, and it's hard to stomach the idea of going out and openly supporting a president in favor of furthering Israel's genocidal campaign.