So you're stealing binaries from GH and calling it your own? Sort of like what every download site already does. "Every day, SourceForge sees over a million visitors and serves 4.5 million software downloads." So everyday a user on average downloads 4.5 software packages? I highly doubt your numbers. Personally, I've downloaded perhaps 5 within the last year and I am an rabid consumer of OSS. I am not impressed with your performance.
The binaries in question aren't GH's or SF's, they're the project's, and since this synching is under the project's control, I don't see the problem.