I’m very skeptical about that claim. It’s of course true that the first amendment and basic rights in general (usually?) only apply to the government. I know too little about US law to say with certainty whether there are exceptions in the USA. (I know with certainty that in certain, very limited circumstances some basic rights apply even between private entities in Germany.)
The submitted article, however, quotes a law professor who explicitly portrays this as a first amendment issue which doesn’t support your hypothesis that the first amendment only applies to the government in this case. I’m relatively certain that Facebook is free to block Lamebook on their own site all they want. Freedom of speech doesn’t come into play. I’m not so sure about that when it comes to the trademark.
The submitted article, however, quotes a law professor who explicitly portrays this as a first amendment issue which doesn’t support your hypothesis that the first amendment only applies to the government in this case. I’m relatively certain that Facebook is free to block Lamebook on their own site all they want. Freedom of speech doesn’t come into play. I’m not so sure about that when it comes to the trademark.