To be able to answer this question, we should first define what being free means. According to dictionary, freedom means "the absence of necessity, coercion, or constraint in choice or action". In practice this would mean that if everyone was truly "free", no one should or could be forced or told to do something against their own free will, and all of their decisions would be their own without anyone being able to influence them.
This leads to the original question: why can't everyone be free, then? Having complete freedom would, after all, make us all happier than we are now, and create a true utopia where everyone is free to do as they please. A world where everyone is independent and free of responsibilities.