In short, we aren’t on track to an apocalyptic extinction, and the new head is concerned that rhetoric that we are is making people apathetic and paralyzes them from making beneficial actions.
He makes it clear too that this doesn’t mean things are perfectly fine. The world is becoming and will be more dangerous with respect to climate. We’re going to still have serious problems to deal with. The problems just aren’t insurmountable and extinction level.
I personally don’t want kids, and while that may be a bit of hyperbole, kids being born now are going to be living in a vastly different world 35+ years from now. I think people denying the impacts and going “eh, we’ll figure it out” are worse than the doomers.