I've read that Boing Boing skated this slippery slope by introducing editorial *defacement* but not editorial *deletion*. What they actually did, at least at first, was that an editor would push the "remove vowels" button on the offensive post, which would make it look silly and would clearly show everyone that the social consensus regarded the post as unacceptable, but would not actually remove it.
Apparently, that was a big success for that crowd. People hated getting devowelized and started modifying their behavior to avoid it.
I would suggest "remove the vowels" for lwn.net, but what about some sort of "fold it out of sight by default"? I guess the important part is a consensus among the community that this thing should be ignored and not responded to, and ideally not seen at all unless you are morbidly curious. If this consensus is visible to the original poster as well then this might motivate them to change.
Just brainstorming. I think you'd probably better do *something* before too long, because status quo probably won't continue to work, and it might be easier to manage before it gets bad than after.
Heck, maybe you should just try what worked for Boing Boing. Editors get a button that removes the vowels. :-)