The cheerleaders do it because it gives them exceptional future prospects, both for dating and marrying upwards, as well as in other careers. There are few better ways to become a professional sex object than being a cheerleader for a football team.
For those of us raised with college being the goal and abhorring reliance on our appearance to get by, this is a foreign concept. But it's very common in many places within this country (and the rest of the world.)
Think about it like internship and it starts to make a lot more sense.
The article strikes me as bad anthropology with pretty girls being the hook - e.g. using the cheerleaders to sell their story the same way everyone else uses them.
If we wanted to change something real, we'd be looking at why minimum wage is not applied to seasonal workers and ask ourselves why we are more concerned with the plight of pretty girls on a (career?) track instead of with people who will be stuck in crappy jobs with low pay for the rest of their lives.
[edited because I left extra words in a sentence rendering it unreadable]