There are likely studies which would better support your case. Can't really tell as you didn't include the definition of the the numbers, but they appear to be total injuries. Any kid can hop on a bike and they are cycling. To play football, you need other players, a field, a time, etc. The number of hours of cycling in a year likely dwarf the hours of football.
Youths 14 and under do not possess the size and speed of high school athletes. Many give up bicycles as a mode of transportation when they get their drivers license. A study of 14 to 18 year olds would not likely show the same distribution of numbers.
Perceived risks often differ from actual risks. We are quick to latch onto seemingly dangerous concepts and will spend large amounts of time and money to reduce that risk, while ignoring simple things that pose much greater risks. No parent would allow their child to play violent football without a strong, well padded helmet and other protective gear, but kids ride bikes wearing shorts and a T shirt, with flimsy hunks of Styrofoam or nothing on their heads all the time. Perception doesn't always match reality.
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