In reply to Justin Tadlock.

because so many plugin authors do not provide their source code along with their build/production code.

Isn't this against wordpress.org plugin repository rules?

Code must be (mostly) human readable.
...
We require developers to provide public, maintained access to their source code and any build tools in one of the following ways:

- Include the source code in the deployed plugin
- A link in the readme to the development location
We strongly recommend you document how any development tools are to be used.

Why are these plugins allowed?