Two separate incidents. If anything the Hammonds are getting off light. In 2001 they set fire to cover up their illegal killing of deer. That's when their teenage relative who was a part of it testified in court that the elder Hammond (I think) gave out strike anywhere matches. The second time in 2006 was part of a back burn when there was a burn ban because there were fires in the area. Sure, you can say "Well they were just protecting their property!" But the problem here is that a fire like that can very quickly spread out of control -- which it did. Here's the thing on why they're getting off light: They can be charged separately for each incident thus leading to two convictions each 5 years making their prison time 10 years. What did the prosecutor reach with the Hammonds? That they would serve their sentence concurrently, which means that they'd be charged with one count for the two incidents. Moreover...
"Given the seriousness of arson, a five-year sentence is not grossly disproportionate to the offense. The Supreme Court has upheld far tougher sentences for less serious or, at the very least, comparable offenses. See Lockyer v. Andrade,
538 U.S. 63 (2003) (upholding a sentence of fifty years to life under California’s three-strikes law for stealing nine
videotapes); Ewing v. California, 538 U.S. 11 (2003) (upholding a sentence of twenty-five years to life under California’s three-strikes law for the theft of three golf clubs); Hutto v. Davis, 454 U.S. 370 (1982) (per curiam) (upholding a forty-year sentence for possession of nine ounces of marijuana with the intent to distribute); Rummel v. Estelle, 445 U.S. 263 (1980) (upholding a life sentence under Texas’s recidivist statute for obtaining $120.75 by false pretenses). And we and other courts have done the same. See, e.g., United States v. Tolliver, 730 F.3d 1216, 1230–32 (10th Cir. 2013) (upholding a 430-month sentence for using arson in the commission of a felony); United States v. Major, 676 F.3d 803, 812 (9th Cir. 2012) (upholding a 750-year sentence for offenses under 18 U.S.C. § 924(c)), cert. denied, 133 S. Ct. 280; United States v. Meiners, 485 F.3d 1211, 1212–13 (9th Cir. 2007) (per curiam) (upholding a fifteen-year sentence for advertising child pornography); United States v. Uphoff, 232 F.3d 624, 625–26 (8th Cir. 2000) (upholding a five-year sentence for arson of a building)."