I don't think it's equating soccer to liberalism, I think it's equating a certain type of "liking" soccer (which really doesn't involve being a fan of the sport so much as using it to bash America) with liberalism. And within that context it's accurate, every World Cup the sports world gets filled with columns by well documented liberal sports writers talking about how stupid Americans are for not liking the sport, not that they actually watch the sport of course they just want America to know that not liking it is stupid.
Bingo.
Textbook strawman. Well done. If you ever see an article that tells you the same, please post it.