All of that etiquette sounds nice if you're being paid to do this work, but I don't think anyone is obligated to "properly" disclose a vulnerability they found

All of that etiquette sounds nice if you're being paid to do this work, but I don't think anyone is obligated to "properly" disclose a vulnerability they found on their own time/dime, nor do I think it's a moral imperative for anyone to do so.