“The BUIP process has turned into a sad joke, with proposals more and more absurd being voted on. BU leaders are complacent and, while saying that the attitude of the [Bitcoin Satoshi’s Vision (BSV)] community will cost them developer support, they continue to enable the toxic behavior by supporting BSV.”
Hes butthurt that some BU members won't join his anti-Bitcoin cult.
This seems to be a parallel of the dynamic we see in politics with identity groups. So long as you can justify in your own mind that your own group is more virtuous than the other, then any association of members of your group with a less virtuous group, cannot be tolerated, thus such members are ejected. The inevitable result is that the main group splinters into many pieces so they can retain power and control over the remaining portion of the group.
It seems that to avoid splits (and power struggles) that removing the ability to make contentious changes (i.e., protocol lock down) is the only sane choice. Different groups can maintain power over their own mutually compatible implementations. Anyone who decides to go their own way from that point can do so, but there's no debate that they're starting a new project if that's what they choose to do.
It's actually the standard in today's world. Not just these guys. The world is overrun by social justice warriors and people who demand things they're not entitled to just because they have more voice.
Bitcoin is the antidote.
Edit: the original sources explain it better