It's a reflection of American football's origins.

The first football type of game that colleges played in North America was almost identical to what became soccer: You scored by kicking a goal. But every school had its own rules. That was true even over in England, before the Football Association was created to establish a standard set of rules. Over here in the USA, we had no such governing body, so the schools took it upon themselves to sit down and draw up their own set of rules that everyone could agree on.

In an age when overseas communications took weeks, if not months, Americans lived in relative isolation from their football counterparts in Europe and thus weren't able to easily keep tabs on how the game was progressing there. So Americans (and Canadians) took it upon themselves to sort things out on their own and draw up a set of rules that appealed to them. Although most schools in North America were playing some variety of soccer, others, including Harvard, preferred a game that was more like rugby. When the schools first met to discuss a set of rules, Harvard pressed to base their common rules on the English rugby code, and they prevailed. From that point on, the American version of football began to develop out of rugby instead of soccer.

The same process of codifying rules had happened in England, too: After the Football Association was formed, some clubs disagreed over which rules to use -- primarily, the rule that governed the use of hands in the game. Those who favored prohibiting the hands formed the Football Association, and those who wanted to use the hands as part of the game eventually went on to form the first Rugby Football Union.

The American game could just as easily have been called American rugby, but since everyone was already calling it "football," the name stuck. Besides, in the early days, the American game was much more kicking-oriented than it is now. When there was no forward pass and kicks could be taken from anywhere on the field, teams would frequently dropkick to try to score, or they'd use a deep punt as a defensive strategy, if their running game was getting bogged down. It was only when the forward pass was legalized and kicks were limited to those taken from behind the line of scrimmage that the feet began to play a less prominent role in the American game. But again, everyone already called the game football, so there was no reason to change it.

Just keep in mind that what we call "rugby" is actually "rugby football," yet rugby players handle the ball as much as they kick it. What most of the world calls simply "football" is technically "association football," from the name of its founding and governing body. When soccer and rugby split, the association game simply adopted "football" as its name, while rugby football focused on the first part of its name. That doesn't mean one game is football while the other isn't. They're still both football games with a shared origin.

What's more, since the soccer/rugby split, other football-related games have evolved to emphasize other parts of the body to propel the ball. In fact, of the world's six major football codes -- soccer, rugby league, rugby union, Australian rules football, American (gridiron) football, and Gaelic football -- soccer is the only one that prohibits use of the hands. And they all employ kicking strategies to a greater or lesser extent.