Interesting, I had not heard of it. I guess it probably needs a JavaScript implementation to start.. the thing too is, I'm not convinced that being able to rebroadcast your notes is a bad thing. Say that you get kicked from a group. In a traditional messaging platform, your messages are gone (or at best, you have a screenshot). In nostr, you can take it with you. You could fork the whole group if you wanted to do so.. those that perhaps disagreed with your being kicked, could follow both forks. It's a new paradigm and it's baked into the core of nostr.
We don't need to pretend that delete works. Delete was a fake construct, and there were plenty of Twitter bots that showed deleting was not really possible there either (as they would scrape for all deleted tweets and broadcast them for all to see). This is not a comment related to MLS perse, just a point about how fundamentally different the nostr protocol is.. on discord/reddit there is delete, assuming the same type of bots don't exist there.. but on nostr we have a truly open protocol and therefore we cannot pretend that data will be deleted. The closest analogy is that content even in a group chat, is grouped by consensus, and that consensus can change at will and be changed by all participants.