The world of academic publishing is weird, and while I could try to explain it, I don't think I would do a good job. But to me, it often seems like a scam.
Basically, a bunch of companies who run academic journals receive articles from scientists like myself based on work we have performed, paid for and written up. Then the journals take the research article and send it out to other scientists, who read and review it for now cost, and then send it the journal. Then the journal publishes the work, copyrights the article and attached figures and charges money for people to access it.
There has actually been a large push for open-source publication - which I think is a fabulous idea - and many journals have begun to make their articles available on line for free. As I said, this is great.
But apparently there are companies who are actively fighting against this ... which I feel is kind of evil ... take a look at this article and see what you think.