Martial art organizations are a confused mess, TKD organizations included. Due to egos and the desire for power, there are probably a hundred or more TKD organizations in the US. Most had humble beginnings with noble reasons for their creation, but as they grew in membership, the people in control began to see that there was more money to be made if you rip-off students with exorbitant organization, school, testing, and tournament fees. Since there is no central TKD organization (the ITF is even split into two warring factions), there is no one organization that is necessarily better than the others. Each has its pros and cons, but most want a lot of money from member schools so the organization’s officials may gain even more money and power.
Organizations do have a purpose; they furnish member schools with a central rank certification point and common rank requirements, offer a way for like-minded schools to hold tournaments, and possibly offer ways to help each school grow. Other than that, they are not needed for students who stay in one location for their martial arts career.