Public zaps are public by definition, that's a totally different situation, imo.
Discussion
... the question is what is this platform offering . #nostr is built on #bitcoin ethos .. the offer here is no KYC for information sharing just the way btc is a no KYC platform for financial transactions #permissionless
Keeping this design "public" solves numerous technical as well as legal challenges - I am sure you are well aware . At the same time , users can adapt to ensure their privacy ( point in case is #Satoshi .. just to give a larger than life example ) .... but that is NOT a primary design criteria. It is an adaptation..
There are many tools for extreme privacy .. vpns , tor, simplex , signal , WhatsApp ( ðŸ˜) .. they all are fit for purpose and they may be used on case to case basis . But imo privacy is a never ending fear - for example if I whispered something in your ear , what is the guarantee you wouldn't share it with the entire world on #nostr :-)
The only way to Nirvana in the context of privacy is to never share anything with anyone ( including self :-) .. absolute silence of mind and body .. that is what monks on Himalayas do :-)