This is absolutely untrue but gets parroted by many as somehow accurate.
1) Congress, not the FAA, statutorily defines aircraft and national airspace. Essentially, Congress, not the FAA, broadly defines aircraft and model aircraft and drone aircraft are aircraft by Congressional definition. An aircraft in national airspace (essentially,anything outside under Ad coelum doctrine) IS subject to FAA regulation.
2) In 1981, the FAA struck a compromise with RESPONSIBLE model aircraft operators who by definition are subject to FAA regulations applying to ANY aircraft. Essentially, the FAA said, hey, if model aircraft hobbyists act responsibly and voluntarily fly away from people, away from noise sensitive areas, and away from occupied aircraft, we, the FAA, will not prosecute hobbyists or develop onerous formal regulations for model aircraft.
3) Enter the drone aircraft operators who incorrectly parrot "we don't understand the law, don't want to obey the voluntary guidelines, and want to do what ever we want to." The legally flawed argument here is because no specific regulations exist, then no regulations exist. This is absolutely false and misunderstands how the law works and specifically misconstrues administrative regulations.
4) In 2012, Congress, responding to illegal and extremely risky activity by drone aircraft operators, specifically defined model aircraft BY STATUTE. The statute specifically defines model aircraft as aircraft NOT used for commercial uses and flown responsibly AWAY from people and other aircraft. Any other use is a commercial use and now, per Congress, is subject to FAA normal regulations for any other aircraft activity.
5) In 2014, a NTSB administrative law judge deciding on a $10,000 fine for alleged reckless operation of aircraft in 2011 (note the date carefully), initially held the general regulations did not apply under 2011 law--called the Pirker opinion. First, this Pirker decision was appealed and is stayed so it has no effect until decided on appeal. Second, Pirker itself specifically states that the 1981 guidelines DO apply. Third, even if Pirker would somehow be upheld on appeal (unlikely), Pirker applies to activities occurring BEFORE 2012 when Congress specifically defined model aircraft by statute (a statute usually trumps a regulation). Thus, while drone aircraft activists make wild claims about Pirker, Pirker is really of little or no value.
The sum: drone aircraft are aircraft, are subject to statutory law, are subject to FAA regulation, and unless meeting the very specific criteria of the 2012 statutory definition of model aircraft, cannot be flown as many are flying them today--especially cannot be flown for commercial purposes, around people, in noise sensitive areas, or near ANY other aircraft including other drone aircraft.