There is a very good point about the difficult-to-impossibility of securing email.

BUT:

> Ordinary people don’t exchange email messages that any powerful adversary would bother to read,

This just one hundred percent incorrect and it completely misstates the problem.

The problem is not that Alice and Bob are the focus of intensely focused surveillance, in the sense that they are up against a powerful adversary themselves.

The problem is that Alice and Bob live in a society where those who can and want to make such decisions, are implementing drag-net surveillance at every possible corner of society that they can get away with.

There is a powerful adversary and it would very much like to to read any and all of our communication.

In almost all cases this is consequence-free for Alice and Bob - but this is not Freedom.

My communication is mine it's not there for google so scan for ways to sell me useless shit, and it's not there for Big Brother for training their precog-ML models on it.

The threat model is not "The CIA wants to rubberhose me into revealing information" it's "The NSA routinely opens all of my letters, just to make sure I am not a terrorist/commie/vagrant/etc".