He's one of the people promoting this nutty claim.
It's based on the implausibility of her claim and her lack of general credibility, yeah. The other guy ran, but if you want to bet that something will come of this, I'm game.
My argument is that the claim is implausible and no credible source has come forward with it (at least that I'm aware of). Not sure where you're getting that other stuff or why it even matters. Let's say it's true that I have fragile emotions; it's still true that we haven't seen any credible reporting on this, and the claim is implausible. Still true that a reasonable person wouldn't believe something with good evidence.
Biden helped with the invasion of Iraq? And Greenwald was cheerleading for that same invasion when it happened. He's also been cheerleading for Russia's even worse invasion of Ukraine. But granted that someone with no power has limited responsibility. I think the designation is more about one's character, though.