I'm not sure what your point is here, so apologies if I'm missing something.
I'm not saying that he had no idea it had happened or no clue someone might knock on his door to interview him. But I'm pretty sure that if one day you're just some Bernie guy with an anti-genocide poster in your window, then the next day the FBI is raiding the house next door & the national press wants to interview you about the killing of two Israeli embassy workers, it's going to feel sudden, unexpected, not something you were really ready for. Not that he didn't have time to comb his beard.
The point is that lots of ordinary people - including Bernie libs - can talk about Israel, it's genocide, and even this shooting, without media training, without experience of being interviewed, without much preparation. And they can do it in simple, direct, moral and empathetic terms without getting tripped up or boxed in by the media.
And yet the vast majority of politicians and pundits, even those with the right position, almost universally cannot. I have my suspicions as to why of course, but it says something pretty damning about the ineffectualness of liberal and even actual left politicians and media figures.