If the method you’re talking about becomes widely used, the bots will come out of the woodwork to manipulate it, so we will need at least a rudimentary social graph analysis to weed them out. The baseline grapevine score is perfect for that. It ranges between 0 (bot) and 1 (not a bot), and in-between means not entirely sure yet either way.
Discussion
you are confusing my distinctions by equating a lack of public advertising of association with a lack of useful data for your proposed social graph scheme
saying who is welcome to message you and who is not, is a public notice, but who you actually read and who you don't want to read, and what your priorities are for filtering them should and could be private, but is not
it is a zero-metadata-leak aside from "this person is online" when a user stores an application specific data encrypted blob to a relay, and it would solve a lot of the state problems not just with specific applications but with multiple clients and key rotation as well
your assumption is that you should advertise to the whole world who you hate and who you love, and this is actually kinda dangerous and blunt way of approaching the problems
what makse it out to the public is two things:
"you can message me" "don't waste your time messaging me"
outside of that, there is a huge amount of useful data that could easily be added to these graph calculations just by evaluating the number of times your npub and other people's npubs appear in events and graphing that over time as well as on average
my point is that some of the aspects of the utility of this data do not necessarily or, more exactly, are not actually helpful, or privacy-respecting, if you don't make the distinction between what should be private and what must be public
if you expect everyone should wear their heart on their sleeve, this is fine for your personal life but imposing this onto a protocol is irresponsible and actually kinda malicious
I make no assumption that everyone should at all times wear their hearts on their sleeves.
My assumption is that you, as a sovereign individual, can and should decide what you do and do not want to reveal, and to whom, and when, and under what circumstances.
My task is to help provide the tools that allow you to do make these decisions.