I know David Nichols, the head of the ABP from Johns Hopkins.
When I was in med school he became somewhat infamous for denigrating primary care, saying something to the effect of "we're not training general primary care doctors, we're training leaders in academic medicine"
Given that, it's not surprising that under his leadership the ABP is going to enshrine more worthless academic training that's completely unnecessary.
I think part of what starts this nonsense is that ivory tower academics want to create new job security for themselves, so they conjure up all this BS about how pediatric residency is not sufficient for certain jobs. It's in their best interest to keep raising the ladder higher and higher.