This is unprecedented because there is, to my knowledge, no formal governance structure or policy around management of BIP Editors.
I see no need to rehash the lengthy list of disputes in which Luke has been involved; it seems to me that ultimately this comes down to reputation.
In my view, Luke has proven himself to be poorly suited to working well with others. It's nearly impossible for him to communicate clearly because he often operates under completely different definitions of terms than are standard, and this twisting of terminology seems to be his modus operandi for remaining "honest" (in his view) while making outrageous statements.
Beyond that, his open hostility and animosity toward fellow contributors and often even the whole of Bitcoin Core as an organization make it incredibly puzzling to me why he should have any association with it whatsoever.
This isn't a democracy and I have no vote. But it seems to me that if the other BIP Editors are uninterested in continuing to work with Luke, they are under no obligation to leave privileged access open for him to potentially abuse.