Because as a society we generally already agree that human outputs need be restricted as well. Being artificial in origin doesn't change the nature of trademark infringement or outright theft (generally speaking — some content that is illegal now because it victimizes others, being turned into victimless but gross content is an edge case).
To be clear, I would argue the regulations in question would fall under the human/legal entity responsible for the creation or dissemination. Having censored output on the AI itself seems significantly less productive.