> In the physical world, there is no common expectation of privacy in public spaces.

Oh, please. This is a false equivalence if I ever read one.

When you're in public nobody is building a profile on you. Nobody is tracking where you go, what you buy, how you behave, and what your interests are. Nobody is then storing this data and getting rich from it in perpetuity.

If privacy online were limited to companies knowing just your IP address and general location, and not storing this data, _that_ would be equivalent to public spaces in the real world. The fact it's not, and companies actively try to gather as much information they can about you, often in scammy ways that forces governments to come up with new regulations, where getting fined for violating them is just the cost of doing business... is beyond nefarious and any reasonable defense.

> privacy is not a fundamental feature of anything

Huh? Privacy has been a fundamental human right for millennia, codified as part of many legal jurisdictions.

> Any interaction with another person involves the exchange of information, and the amount of information exchanged is neither fair nor necessarily finite.

Again, the difference is in how this information is used. The keywords here are _reach_ and _consent_. We implicitly consent to sharing a limited set of information when interacting with another person or in public, but when that information and its use goes far beyond what we implicitly agree to, then this needs to be clarified, and explicit consent must be given.

> Understand that privacy cuts both ways: most of the world is apparently fine with having no expectation of privacy on public places--online or offline.

This boils down to two things: a) most of the world doesn't understand the implications of the transaction they're a part of when they use online services. The use of their data is hidden behind cryptic privacy policies (which are often violated and don't explain the full picture), and data collection happens in obscure ways without any consent. And b) even if they're aware of this, most users simply accept the transaction because "they have nothing to hide", or the value they get from the service is greater than their privacy concerns. Users are often never given the option of an alternative business model, and even when they are, the data collection machine never stops. Companies know that the allure of getting something for "free" is far more profitable than putting up a paywall, and so they justify extracting as much value as they can from their users' data. We're stuck in an endless cycle of having "free" services where the business transaction is far more valuable to the company than its users. And it's in the companies' best interest to keep the users, the general public and governments in the dark as far as the extent and details of how value is actually extracted. This is the most vile business model we've ever invented.

> If you want good examples of what it looks like when privacy in public spaces is the norm on a large scale, look no further than the cryptocurrency world.

What privacy? The blockchain of most cryptocurrencies is a public ledger where all transactions are visible to everyone. Transactions are done almost exclusively via exchanges that follow strict KYC regulations. So it's pretty easy to identify the person behind any transaction.

Following your logic, should we ban all cash transactions, since they're even more private than cryptocurrencies?

You have a twisted sense of the world, friend. My guess would be that you work for one of these companies, and this is how you rationalize the harm you're putting out in the world.