Hockey, stock car racing, mixed martial arts, and maybe even bowling are all more popular in the United States than Soccer or Badminton or ping pong. and if you're going to include things like badminton and cross country... then hell... why not gymnastics, lacrosse, rugby, diving, water polo, croquet, competitive parcheezee, midget tossing, etc...
I agree. I would include Hockey, Racing, MMA, Bowling. As well as Skiing, Snowboarding, Cycling, Sailing, and Fishing. I wouldn't call Badminton, Ping Pong, or Cross Country the "main sports" in America, though Soccer does fit. Also, cross country wasn't even accepted when i typed it in, despite being displayed as an answer.