It's partially untrue, yes. There was an actual vote from all the active developers to remove Michael from leadership, and that included the infrastructure developers.
But yes, the fork was very badly done.
Then why did so many remain with the ffmpeg project instead of going with libav ?
"I think the statistics indicate that the situation is much worse than I expected. Please keep in mind that because of the daily merges, all commits that are made in Libav also appear in FFmpeg, but not the other way round. With a finger-in-the-wind estimate of subtracting the numbers in the Libav table from the FFmpeg table, the distance between Michael and the other FFmpeg developers because even more extreme."