The rants weren’t breaking news to anyone who was familiar with PyTorch or adjacent communities. He seized upon a weak moment for AMD to try to launch his own company. Unfortunately he launched his effort with an attack on the company he was effectively trying to partner with, making the entire venture DOA.
It’s too bad, too, because it would have been interesting to see if anything could have been accomplished with a more friendly offer of cooperation. He’s obviously talented as a developer, but effectively going on the attack for the company that forms the foundation of the business you’re trying to build is obviously not going to end well.