1: Code Is Free Speech dot com only hosts free and publicly-available information (how to build a weapon using a 3d printer) and does not sell any prohibited products or services.
2: The website is protected by both the first amendment (freedom of speech) and the second (freedom to bear arms). Prohibition of the information on the site is unconstitutional. As a business, Facebook is not bound by the U.S. Constitution, but as an American company, it ought to respect it.
3: It is misleading to say that as a private business, Facebook is merely imposing their community standards. Facebook probably censored the site because their political/legal team fears real censorship from Congress if they do not act independently, just as Hollywood censors movies because of the explicit threat that Congress will do so otherwise. Private censorship under implied threat is still censorship.
4: By labeling links to the site as “spam” and “malicious” Facebook is lying to their customers, since the links I post to my own profile cannot be spam (by definition, they are not unsolicited), and the site hosts no “malicious” malware (I personally checked it).
5: None of the actions the site enables are illegal. It is not illegal in the U.S. to build non-prohibited weapons for personal use or to distribute information on how to do so. Information on how to build weapons can be found at your local library. While courts have issued an (unconstitutional) order to prohibit an unrelated site from publishing this information, the site in question is not subject to any such order, and Facebook has not been prohibited from publishing links to any such site.
6: The right to self-defense is a fundamental human right. All freedom-loving people and businesses out to support the people’s right to protect their loved ones from harm. It is proper to condemn companies which take a stand against basic human rights.
7: The way Facebook has chosen to block the site resembles the dishonest way that totalitarian regimes censor the web. For example, the Chinese government does not censor the Internet directly. It directs (nominally private) ISP to censor connections to prohibited sites in a way that mimics technical problems. You will not see a “this site is banned” message when you try to visit Facebook in China. Your web browser will report one of a variety of technical errors in trying to reach the site. Many sites are partially or intermittently blocked, or access is simply degraded. As a result, many Chinese are not even aware that 90% of the foreign Internet is censored. The way Facebook has chosen to censor links to the site mimics this approach and sets a dangerous precedent for the future. The people have a right to know when they are denied their freedom of speech.