Leaks happen. The way Martin has responded I personally don't agree with. I understand being upset, and frustrated that you didn't get to control the release of your own material, but choosing to cancel the release of the song as a single? Why? Chances are the people hunting down a leak of an incomplete Martin Garrix featuring Mike Shinoda track are already fans of one or both artists. I can't speak for everyone obviously, but even if the full version had leaked I still would have bought it upon its official release.
This felt like a retaliatory move, honestly, and I don't feel it's right to essentially punish his fan base and deny the song's official release because an incomplete studio version was leaked.