The moral principle of free speech existed before any supporting law existed, otherwise the law couldn't have been created.

I respect your legal and moral property rights, but I might think someone is a bad person for censoring speech within their own house (for example, a Christian household in which a curious skeptic teen is denied access to secular literature).

You and I can disagree with the importance or applicability of any ethical principle, it doesn't negate the nature of the principle. Recognizing an ethical principle as such (don't harm animals) doesn't require we adhere to all of it's possible consequences (eating vegan, maybe).