Times V Sullivan and the Equal Protection Clause

I’m having trouble understanding how Times v. Sullivan, the SC decision which reinforced the the first amendment protections of speech and of the press by introducing the “Actual malice” requirement to prove slander and libel perpetrated against “Public figures” is compatible with the Equal Protection clause in the 14th amendment. Why doesn’t the existence of two classes of potential victims of the same crime with two different burdens of proof required to protect them not violate the equal protection principle?

Times V Sullivan and the Equal Protection Clause