I understand that, but the "effectively" in that sentence is an acknowledgment of that being an indirect consequence; one party being able to withdraw their material wouldn't immediately revoke or otherwise invalidate the license itself. It would just make it
possible for other people to withdraw their own material, including those who've released material that other people count on.
But that's not the point.
The point is that merely making the threat of withdrawing their own material—when that threat comes from a multinational corporation—doesn't need to result in any actual court documents being filed to cause sufficient
fear, uncertainty, and doubt that the result is a
chilling effect among publishers, even if the ability to follow through on the aforementioned threat is legally dubious. Exactly like what happened with the OGL. Hence why the idea of the CC somehow being safer than the OGL is an illusion.