> Once your work is published under Creative Commons license, it is irreversible.
I am not sure how it is under Japanese law, but in some countries a creator cannot be stripped of his rights by agreeing to a license. Even without that there is often a way to rescind any gift given in good faith if the receipients behavior warrants it.
In case of Japanese copyright law, that is 著作人格権(moral rights). A right that protect his work isn't used in a way the author don't want it.
It includes right to be not published(like a personal letter intended to be secret), attribution, right to be identical preservation(modifying in a way author don't intended, like adding extra arm to 3-arms monster)
You see, these rights are covered in Creative Commons, by agreeing and publishing his work under Creative Commons, the author explicitly promised he won't use these exclusive rights against the users.
If he didn't agree on the spirit of Creative Commons, why did he contributed Mozilla in CC license for 20 years? Did he intended to taint free software by incompatible non-free work?
This is exactly what happens if you ignore the free software definition explained by RMS.
I am not sure how it is under Japanese law, but in some countries a creator cannot be stripped of his rights by agreeing to a license. Even without that there is often a way to rescind any gift given in good faith if the receipients behavior warrants it.