This is because there currently is no way to do this, and this commit doesn't remove the AND capability either.
For example, take the original blacklist "a -b -c".
Currently, that means "Don't show a unless both b and c are present", but now it means "Don't show a unless either b or c are present".
For the original meaning, you now have to do this with two blacklists: "a -b" and "a -c"