Privacy is a right in some meanings of the word, such as the fourth amendment that protects against unreasonable searches and seizures. For example, the police cannot enter your house without a warrant except for a few very specific circumstances, such as:

• someone is likely to be actively physically harming someone, or about to physically harm someone
• you're likely to destroy evidence (they can only bring you outside, they cannot search the house for said evidence)
• if you invite them in, and making an emergency call is one such example (e.g. someone is having a heart attack and they come to assist medical personnel)

And this isn't just real property, but anything that could be considered private property. They cannot search your phone without a warrant or permission, they cannot search your person without at least detaining you (which requires reasonable suspicion, and I think they can only look for weapons unless they arrest you), etc.

So there absolutely is a right to privacy in the US.

That said, there are circumstances where you have no expectation of privacy, such as:

• in a public place
• clearly visible from a private place (e.g. you're in a driveway)

The Internet is essentially treated as a public place (as it should), so the way to maintain privacy is to encrypt your traffic end to end. However, the other end of that traffic can always choose to disclose the data they have to authorities, so someone like Meta or Microsoft could decide to hand over access to data to law enforcement willingly. If the company doesn't offer it willingly, law enforcement needs to get a warrant, just like any other search of private property, and until then, they can only sniff packets that they have access to (i.e. transfers to another service that has granted access).

When people talk about privacy in the US, they're not talking about restrictions on government, because those laws are already in place and well established with legal precedent. What they're talking about is an obligation for certain types of online services to not disclose personal information and to dispose of it at the client's request. This goes under the assumption that you still own content you have submitted, which gets into IP law and, at the current time, terms of use at each entity.

In summary, the US recognizes a negative right to privacy, but it does not recognize or enforce a positive right to privacy. So we have two solutions to solve the problem of privacy, both of which have downsides that I'm not going to get into here:

• pass a law requiring enforcement of a positive right to privacy (something like the GDPR in Europe)
• empower individuals to take ownership of their data so the negative right to privacy applies as expected - lemmy is a step toward that, though the copying of user submitted content is problematic (Matrix is closer with encrypted rooms)

Perhaps we need a bit of both, but to say the US has no right to privacy completely misrepresents the situation.