There is a story here... what happened?
It is, like many of the Great RPG Wars, entirely banal, and really headscratching with the passage of time.
RPGPundit was, as many may know, a consultant for 5e. In the run up to release, he had some inside info on the release of the Basic Rules, and hinted that it would be awesome.
Benoist was, as many may know, neck-deep in the OSR, working with Ernie Gygax Jr. on creating a product based on the latter's dungeon; and consequently, pretty skeptical of 5e in general.
When WotC announced the 5e Starter Set, it was revealed that the box came with pre-gens, but not chargen rules. A number of RPGSite posters decried this as a ridiculous mistake on WotC's part. Benoist, who had up to then pretty much ignored 5e and the playtest, was pretty vocal member of that group. Pundit continued to contend that it would all be cool, that the Starter Set wasn't the "real" Basic Set.
Then the Basic Rules announcement was made. As this involved downloading a PDF to get chargen rules, rather than having them included in the Starter Set box set, Benoist was not impressed. To him, the important thing is that any "Basic" box set version of the game that could be given to beginners have chargen.
As Benoist was a pretty vocal member of the group not satisfied with WotC's plans, Pundit singled him out in a few blog posts that basically said, "No, WotC's strategy here
is awesome, and here's why Benoist is wrong." These blog posts had both a comment section and were cross-posted at RPGSite, there was lots of opportunities for arguing. A veritable OSR vs 5e Quasi-War! The upshot being that Benoist basically threw in the towel as a moderator of theRPGSite and stopped posting there, except for updates and answering questions about his Kickstarter.
There may be some behind the scenes stuff I'm not aware of, nor do I recall the exact straw that broke the camel's back, but that seemed to be the extent of 5e's involvement in any estrangement between RPGPundit and Benoist. Now, of course, almost two years later, no one really gives a damn about the Starter Set not having chargen, and in as much as the Starter Set comes up in conversation, it's about how awesome the LMoP adventure is. So, there you go.