Yeah, in spite of the author's claims to not want to be the humor police, this really just reads as someone who takes their work as a historian of nuclear weapons 'very seriously' and doesn't want it to be joked about. The SNL joke he identified as being particularly offensive ("Having received the Novel Peace Prize, the survivors of the nuclear bombings called the award the second biggest surprise of their lives") is ... pretty anodyne? It's not making fun of the survivors or glorifying cruelty, it's just contrasting the banal things people say when receiving awards with the extreme reality of having endured one of the most awful events in human history. That kind of juxtaposition is pretty par for the course in comedy, let alone dark comedy. And when it comes to engaging with the reality of awful events, not everyone wants to or has the capacity to treat them with the grave solemnity the author seems to expect.

IIRC John Cleese has a talk from years ago where he makes a very interesting point that seriousness and solemnity are two very different things.

In his opinion, killing humor is the same as killing creativity and killing creativity is the same as inviting disaster and/or failure for the sake of your ego.

Not being solemn is not the same as not being serious.

I think your last sentence there really is the right take away here. But even more than that, I think the right way to prevent future tragedies is with humor not solemnity.