The author acknowledges early on that `Random.secure` is there to provide randomness where it needs to be secure, but then spends the entire article fretting over how the other source of randomness isn't. But it's not supposed to be!
Applications have plenty of reason for cheap, stable, or otherwise controlled forms of randomness and shouldn't have to pay the penalty for -- or face the reproducibility limitations of -- secure randonmness when that's not what they need. It's both useful and traditional for standard libraries to either include both forms, or to leave the secure form for other libraries to contribute.
If an application uses the wrong supply of randomness for their needs, that's an application error. And if developers writing security-sensitive code don't know to think anticipate this distinction and avoid the error, then that sounds like there was a project management error in assigning them such a sensitive task.