96% of the world does not consider "America" to be a continent. A large chunk of the world considers North America and South America to be separate continents. Similarly, some countries teach that Europe and Asia are distinct continents while others teach that Eurasia is a single continent.
Spanish speaking countries tend to treat America as one continent. English-speaking countries tend to treat North America and South America as separate continents, which is convenient since when speaking English, America means "the United States."