The reason I watch the occasional soccer match is that having played it as a teen I have an attachment to it, and I enjoy seeing it played skillfully by well-trained athletes, like I enjoy watching anything done skillfully. I don't think that's outlandish or difficult to understand, though women may not relate to it as much as men.
What I find difficult to understand is the fixation on pro sports to the point of some men watching hours a week, paying princely sums to see live games, knowing all the statistics, and having little else to talk about.