I don't think they're kidding, grad. Look at what the rest of their post was about. How it was presented.
Football/sports are important in that they do bring in contracts and sponsorships for the university. Should a team have success, this does expand the fan base, which does increase the popularity of the school. We don't necessarily NEED this to take place, but it certainly exists. There's no question.
Another benefit to sports clubs, specifically good teams, is the creation of tradition and camraderie amongst fans and players. It leads to more interest in a school, a desire to be apart of those traditions.
But again, none of that is necessary. Harvard has decent sports teams, but I wouldn't be going there for the sports, imo. If I wanted to go to a school for sports, i'd pick Alabama, UNC, maybe UF.