Israel showed insufficient loyalty to the orange pumpkin when he was expecting it. He never forgets a snub like that.
Objectively, this shows here is a guy who speaks his mind, consequences (in US politics) be damned.
On Dem side, apart from partisans like Tlaib, only Bernie Sanders had the cojones to call out Israel.

Nobody but nobody can justify Hamas atrocities. The "beheading of babies" itself is not 100% proven yet, but it's telling that few would disbelieve it. These guys are perfectly capable of it.
However - while Israel does not behead babies (I hope to God), I am not too sure that murdering them using bombs is morally justified.
Neither side gives a carp about civilian deaths, so it's hard to choose sides. Unless you are any other US politician. In which case Israel can do no wrong, lest the US Jewish lobby gets against you.

I won't say Trump is a breath of fresh air, but it's always fresh something. Biden is stale and boring and unworthy of any attention.