It seems to me that (well, my) shivers were caused by the style of message, being similarly styled to the, um, more contentious ones elsewhere, and similarly suspiciously worded. I don't know if there are any terseness-requiring limits on the moderation reason field (and if so, whether that could be tweaked from the default), but even:
"Self-suspended as per PM'd user request: "Please permaban me. Cowicide style""
…gives them their parting word, and would look less like a "I consider that a request for a ban" sardonic reply.
(In feeding-back to users in my own roles, I'm personally a big fan of a notepad of standard replies (and text fragments) to reasonably standard queries (like this one: A type-a 'account close at user request') to c&p in and tweak - and in most jobs I end up with a 'standard replies.txt' on the desktop. One day I may move them to Google docs?)
To be clear, I'm trying to feedback, not be critical (after all, you're one of the people doing what others talk about, so kudos is due) - just hopefully helping avoid old misapprehensions.
Or maybe I'm talking too much about a one-off event done for the first time here, by (actual) user request, and in some haste. You be the judge.