Yes, you're missing a crucial distinction: there are different types of defamation. Defamation of a public figure (which the linked law journal article you provided discusses) places a higher burden on the plaintiff than defamation of a private individual. A public figure must demonstrate the falsity of statements made against him,
and must demonstrate malice. The justification is that a public figure is more readily able to defend himself or has others willing to defend him in the court of public opinion.
For defamation of a private individual, the burden of truth remains with the defendant (once the plaintiff establishes a prima facie case). See, e.g., Ellenberger v. Espinosa (1994) 30 Cal.App.4th 943, 953. There are slight variations from state to state, but this is the general rule. (By the way, in case you are wondering, in the legal field, citing a case or statute trumps a law review article or Wikipedia every time.)