Your logic is still flawed:

completely unreadable source is of no use to anyone,

Users use code that is "completely unreadable" to them all the time. Code with lost source is sometimes used and may be considered "completely unreadable". If that was all that was available it would be used often.

If every programmer died today, do you seriously think that software would be unused tomorrow?

What does it do?

Don't you have to execute it before it does something?

Do you know?

You could execute it and find out.

How will you find an error if there is one?

You would execute it. If you can not execute it, it has no function.

How do you know what is an error or not?

If it is not executable it does nothing. Is that an error? If it executes and performs the functions desired then it is correct.

The foremost issue is writing legible code.

The foremost issue is writing code that does something, that executes, that performs a desired function. Legibility is a adjunct toward that end.

You are like a person who says air isn't that important, you are taking it for granted.

Your position is ridiculous. If you must cling to it, I hope it serves you well.