But what we really need — and it is not clear what Facebook has in mind — is privacy for true person-to-person messaging apps, not messaging apps that also allow for secure mass messaging.

At the moment, critics can (and have) held Facebook accountable for its failure to adequately moderate the content it disseminates — allowing for hate speech, vaccine misinformation, fake news and so on. Once end-to-end encryption is put in place, Facebook can wash its hands of the content. We don’t want to end up with all the same problems we now have with viral content online — only with less visibility and nobody to hold responsible for it.

It’s also worth noting that encrypted messaging, in addition to releasing Facebook from the obligation to moderate content, wouldn’t interfere with the surveillance that Facebook conducts for the benefit of advertisers. As Mr. Zuckerberg admitted in an interview after he posted his plan, Facebook isn’t “really using the content of messages to target ads today anyway.” In other words, he is happy to bolster privacy when doing so would decrease Facebook’s responsibilities, but not when doing so would decrease its advertising revenue.

Another point that Mr. Zuckerberg emphasized in his post was his intention to make Facebook’s messaging platforms, Messenger, WhatsApp and Instagram, “interoperable.” He described this decision as part of his “privacy-focused vision,” though it is not clear how doing so — which would presumably involve sharing user data — would serve privacy interests.

Merging those apps just might, however, serve Facebook’s interest in avoiding antitrust remedies. Just as regulators are realizing that allowing Facebook to gobble up all its competitors (including WhatsApp and Instagram) may have been a mistake, Mr. Zuckerberg decides to scramble the eggs to make them harder to separate into independent entities. What a coincidence.

In short, the few genuinely new steps that Mr. Zuckerberg announced on Wednesday seem all too conveniently aligned with Facebook’s needs, whether they concern government regulation, public scandal or profitability. This supposed shift toward a “privacy-focused vision” looks more to me like shrewd competitive positioning, dressed up in privacy rhetoric.

Sheryl Sandberg, Facebook’s chief operating officer, likes to say that the company’s problem is that it has been “way too idealistic.” I think the problem is the invasive way it makes its money and its lack of meaningful oversight. Until those things change, I don’t expect any shift by the company toward privacy to matter much.