on a public relay, the notes are public. since negentropy is a more efficient way to get the notes i havent seen a reason to turn it into an option. (scrapers are pulling the data already without it). i think clients may all use negentropy in the future. it is an option server side, if you feel strongly about it i can turn it off for your relay(s) and consider making it a UI option in the future. there was a bug in the rt proxy config that i did not realize was preventing negentropy, so i fixed it about a month ago..