Because parkour and freerunning share many movements, ideas, and philosophies, practitioners generally do both. Rarely will you see someone exclusively focus on one or the other. Once practitioners get immersed in parkour or freerunning, they usually take interest in many other kinds of movement based activities such as breakdancing, martial arts, dance, or gymnastics. Parkour and freerunning will teach you nearly all the same things and provide you with the same benefits. In the end, it is best to not worry about restricting your movement to one specific style or discipline. You can learn from all of them; the most important thing to do is just get out and move!

Well I might be totally wrong, but here goes:

in all my looking online I keep finding the idea that free running, parkour, l'art de movement, urban junggling,... are all basically the same thing (kinda like soccer and football are the same the name just depends on the country ) but even if there are some small differences they all have the same core and the idea that the movement is individual to the person .... that is to say ...   that given the same environment , same start point and same destination 2 people may not take the same path, but that does not mean that one is right and one is wrong, just different.......whatever we call it (parkour, free running, urban jungling,... it is about movement, precision,overcoming the obstacles and finding the path that works for you......that is what matters.