George Washinton Carver, Elijah McCoy, Madam CJ Walker, Lewis Howard Latimer, and Garrett Morgan
How many of those do you suppose are actually in the "Top 10" of US inventors
Thomas Edison, Alexander Graham Bell, Samuel Morse, Eli Whitney, Nikola Tesla, George Washington Carver, Charles Goodyear, Lewis Howard Latimer, Henry Ford, George Eastman
... which does corroborate OP's "American inventors" hypothesis.
Secondly google search results are a best guess based on prior search history and other data about you about what you want to read right now given a term.
You wont anywhere find a universal fact about what google themselves thinks about anything without reading material written BY google and not generated results from its search engine.