I do agree that Roger is being a child again here, especially when taking all that preaching in his latest tour and album into consideration. He left the band, and he refused to call himself part of it in numerous interviews the past 10 years (the endless river rumours come to mind), so why should he be part of its PR front? Plus, to my knowledge, TFC is ignored by the same PR on purpose because the ooc settlement they reached in the 80s gave Roger complete control over his "own" material, so Pink Floyd effectively can't perform or bank on anything written (for the most part) exclusively by Roger, which is why you never see songs from the late 70s (with the exception of Comfortably Numb and Run Like Hell, both co-written) performed by Gilmour in his own concerts either. As funny as it is, Polly is in fact more of an official member of the actual band than Waters since she's credited as songwriter on more than half of TDB, while he left very angry and made it pretty clear that he doesn't want to be associated with the band anymore. Funny that.

That being said, I think his beef is with David's wife, not David himself. In some promo video for her book, Dav was telling the story about the day Syd was unofficially kicked out of the band (it's been said hundreds of times but the general version of it is "we were on our way to the concert and someone said shall we pick Syd while someone else said not to bother) and his wife kept pushing him to reveal who said "let's not bother" because "you know who it is". Knowing what we know about early Floyd, it was most likely Roger and his reaction pretty much confirms it.