I tried being nosy and went to the discord server. From what I can gather within the official discord, it seems likely a similar situation to former Minecraft mod loaders drama. Weird, intercommunity drama and general disagreements about the future of the project resulting in a massive split. It seems that there was discussion of potentially improving upon the code of forge and having it run smoother and maybe incorporating an existing project (sodium it seems?) and if such suggestion was actually incorporated that would have potentially disrupted the forge main download site’s ability to generate ad revenue, and such suggestion apparently morphed into tension that had been seemingly brewing for months. Apparently, the guy they parted ways with was given the forge project and basically owns the rights to the name, website, ad revenue on the website, and is in control of community donations. All of it seems like a hot mess regardless, but we will see what the truth is in time I presume.

Take what I’m saying with a grain of salt though, I could be completely wrong.