This isn't my place to argue, and certainly he was involved at the time, but LibAV wasn't really "his fork". Reading the full list of names who signed off https://lwn.net/Articles/423703/ I'm more interested in some other names, including darkshikari's deadname and the other heavy hitters of x264.

And if you browse through the ffmpeg mailing list of that historic month https://ffmpeg.org/pipermail/ffmpeg-devel/2011-January/ you'll find his name mostly attached to esoteric video game format patches and not in the big flamewar threads.

Actually - it looks like you can also see in that same month, his post of the first SMUSH codec implementation, that we're discussing in this thread. That's probably a bigger emotional factor than LibAV.