The non-democratic countries that you spoke of in the post that you removed are, exactly as how you stated, non-democratic. We are a democracy (or a republic, rather) and we have a Constitution that defines our freedoms—freedom of speech being one of these. This "labeling" is an alternative to following the lead of those non-democratic countries and attempting to cencor the internet in its entirety (which as demonstrated by China, does not work). This is not an issue involving free speech. It does not violate the Constitution. It just prevents a child from inadvertently stumbling onto one of these websites and allows web filtering software to function more accurately. The "censorship" is left up to those who install and properly configure web filtering software on their computer's which is an ideal preached by anti-cencorship advocates, myself included.