"Automatic" is used frequently both by the general public and enthusiast folks to refer to both semi and fully-automatic weapons. Both are indeed 'automatic' weapons (aka self-loading). Typically the vernacular for fully automatic is "machine gun". The term machine gun is also what the ATF uses to classify fully automatic weapons.
The National Automatic Pistol Collectors Association:
Automatic Pistols for Sale:
Rugar Automatic Pistols for Sale:
Even the names of various loads/guns refer to semi-automatic weapons as simply "automatic" or "auto", such as the .45 ACP (the round designed for use in the original M1911), which stands for .45 Automatic
"The M1911 is still carried by some U.S. forces. Its formal designation as of 1940 was Automatic Pistol, Caliber .45, M1911 for the original Model of 1911 or Automatic Pistol, Caliber .45, M1911A1 for the M1911A1, adopted in 1924. The designation changed to Pistol, Caliber .45, Automatic, M1911A1 in the Vietnam era." http://en.wikipedia.org/wiki/M1911_pistol
But I guess it's just that John Browning (the man who invented pretty much every type of automatic weapon) and the U.S. Army don't know the difference between full and semi-auto.
Welcome to human language use and all its associated vagaries. Get over yourselves.