Well of course he doesn't - he's a psychopath. A complete lack of concern for others is one of his defining characteristics.
And even beyond that, Biden's a special case.
Another aspect of Trump's mental illness is his entirely self-absorbed conception of reality. For instance, he wanted to win in 2020; and he believes he deserved to win in 2020, therefore, from his delusional point of view, the only possible reality is that he did win, but somebody stole it from him.
And that somebody is Biden, and since another aspect of his mental illness is to childishly cling to grudges over perceived wrongs, he has it in for Biden specifically.
Why are so many different politicians and officials in so many different countries so keen to enable the mass murder of Gazans?
I mean - yeah - military/industrial complex and Israeli lobbying and disinformation and Middle East destabilization and even that screechingly insane christian zionist armageddon thing - there are lots of ways that Israel coerces support for its patent evil. But even all of them added together don't seem enough to explain the scale on which they've managed it, nor the range of different countries they've done it in.
It's as if we have a worldwide epidemic of contagious psychopathy, with Israel as the reservoir.