Not Gabe lmao, Gabe's got nothing to do with this. It was confirmed by the creator of Garry's Mod, Godeau Newman.
...Nah, Garry Newman. But yeah, he confirmed this is legitimate and happening. It does look like there was some kind of impersonator running around for some time before, but with Garry himself confirming the C&D's legitimacy, trying to pin this on the Peters guy seems more like copium than anything else. I suppose we'll see how it pans out, though.