Quite simply: You don't. End users generally get them by extracting them from games such as Guitar Hero and Rock Band, which have these tracks separated. The tracks themselves are provided by the bands or record labels.
The links you provided are ALL based on tracks from the original studio recordings and were NOT extracted from the final master.
While various extraction techniques are being researched, perfect extraction is mathematically impossible. That's because a significant amount of data is lost forever during mixing.
The ability to detect and isolate whatever's left of the individual tracks is a hugely complex computer-science challenge that's a bit similar to computer vision. There is just no known way of doing this right now that even closely resembles the human capacity to isolate these tracks while you're listening.