Biden never had a problem with the mass slaughter of women and children. Here’s him in 1982:

Begin said Biden “rose and delivered a very impassioned speech” defending the invasion. Begin said he was shocked at how passionately Biden supported Israel’s invasion when Biden “said he would go even further than Israel, adding that he’d forcefully fend off anyone who sought to invade his country, even if that meant killing women or children.” Begin said, “I disassociated myself from these remarks,” adding: “I said to him: No, sir; attention must be paid. According to our values, it is forbidden to hurt women and children, even in war. Sometimes there are casualties among the civilian population as well. But it is forbidden to aspire to this. This is a yardstick of human civilization, not to hurt civilians.” The comments were striking from Begin, who had been notorious as a leader of the Irgun, a militant group that carried out some of the worst acts of ethnic cleansing accompanying the creation of the state of Israel, including the 1948 Deir Yassin massacre.

https://theintercept.com/2021/04/27/biden-israeli-invasion-lebanon/