Whew, this is quite a sketchy topic, and it may get heated, but hopefully we can all stay civil here.
OP, you don't have you feel bad. You are most certainly practicing Parkour, and you are most certainly a traceuse. If you're out there training your movements and getting in shape and improving your body and your mind and the connection between them, therefore improving yourself, you're definitely doing Parkour.
However, Jordan is right, in that the founders do indeed have a particular Philosophy. It's a particularly, unparticular philosophy. They believe that Parkour is an individual art, and you practice it to shape your life and to improve yourself and become better and accomplish your goals, according to who you are and what you do. Someone with a martial arts background can practice Parkour or someone who wants to be very social can practice Parkour or someone who wants only to get in shape can still practice Parkour in their own ways. But they have to still be practicing Parkour, which means using our methods of training in order to better themselves in some way, according to their goals and their weaknesses. We all have our goals according to us, and they are always changing and evolving!
So what this means is, no Parkour isn't just absolutely anything you make it. Parkour isn't basketweaving, if you want it to be. Parkour is definitely a thing, and there is definitely a philosophy behind it, but it's a very individualistic one, and you can match it to your goals. Right now, your goals are to have fun, get in shape. Honestly, as you practice more and more, you'll discover more about the art and and more about yourself and you'll find more goals and deeper things. It'll be a really cool adventure, and all of that process, all of that path is Parkour, and you are right in the middle of it. So don't let people tell you that you aren't doing Parkour, because you definitely are. You're just... at a particular stage. And chances are, so are your criticizing friends, they just have too much arrogance to see that they are in all actually, probably at a much shallower level of the art than you. Otherwise, they'd be far kinder.