Question

What does the fact that private companies own most media in the U.S. indicate to you?

Answer 1

That fact indicates that every government decisions that made is most likely would benefit these companies.
In United States, 6 companies controlled 90% of the Media. 
This will give them a lot of power to control informations that could influenced the outcome of the election. So they can pretty much appoint whichever candidates that suited their agenda.