Firefox axes add-ons, developer pushes back

title is a little clickbait-y. Firefox didn't "axe add-ons" (ie, the add-ons isn't going away):

> Mozilla has wiped 23 extensions from its directory of Firefox browser add-ons after finding what it says were inappropriate functions in the code.

Mozilla's complaint is that a developer's privacy policy is the only place where it is mentioned that an add-on performs extensive data collection. The developer's response implies that there might be legal consequences if they disclosed it elsewhere without using proper language.

What legal issues could the developer worried be about?