Don't get me wrong you must be a clever chap to put a program together like this. You're also quite right, it's just the same as big groups of people sharing information with each other.
Still gives those using these types of things an advantage over everyone else playing the game as it was meant to be played.
If FD wanted me to be able to see all the trade prices of everyone that's ever been to any station since the game came online... Wouldn't they have added that feature to the game?
Then you get normal players, like me, that don't use these 3rd party trading tools, that simply cant find decent trade route anywhere, ever. Why? Because those that use these types of tools trade them into extinction.
Your program might help you, and your friends that use them, but, at the same time, they make the game much more difficult for everyone else that doesn't use them.
I'd have to disagree with the sentiment that it disrupts the game play. If anything, it invigorates it.
What FD wants, and what you want, are arguably different things indeed. There's a deep philosophical rabbit hole we could run through for ages just on that very subject. Just because it hasn't been produced yet doesn't imply its not wanted. The official stance, at current, is that an API is a good idea. That being said, it is something they want us to experience, but do not have the time to invest in just yet.