Thanks to midnightmagic who directed me to this very helpful video about identifying and then dealing with "poisonous people" in open source software projects:
http://youtu.be/ZSFDm3UYkeE
Advice on disinfecting:
http://youtu.be/ZSFDm3UYkeE?t=34m22s
Watch the whole thing for examples of "poisonous person" behavior, like repeatedly flooding mailing lists/forums with their opinion or comments, not listening to the opinion of others, or making sweeping "the world will end if..." statements about the project.
I'll be blunt: I think Luke Dashjr fits the definition of a poisonous person, and I think Bitcoin would be better without him. At the very least, we wouldn't be creating two BIPs for every technical issue, one for Luke and one for the rest of us (see BIP 16/17, and now we have BIP 20/21, too).