Which logical fallacy is used in the text?
Free speech is good not just for the individual, but for all of society. After all, it's in the interest of the community that everyone should be at liberty to express his or her beliefs.

 - appeal to nature: the assumption that natural things are always good
 - ad hominem: an attack against the person making the argument, rather than the argument itself
 - circular reasoning: an argument that supports a claim with the claim itself
The text argues that free speech is good for society because society is better off when people have free speech. However, the "evidence" is just a restatement of the claim itself. This illustrates a type of logical fallacy known as circular reasoning.