Ummm.... when you don't know the tool, you're not in a good place to judge what a 'good' tutorial is. This is the same reason we've got generations of bad PHP developers out there - they can't tell what's good or not.
"scores of software developers out there who have learned their craft enough to want source control"
How many people 'want' to learn source control, and how many people are told 'this is what we use here, go learn it'? I suspect far more of the latter, especially with git. People would not flock to git purely based on the documentation quality. Further, I suspect that had git just been written by some random dude off the street with no major project behind it, it would have never taken off. Using it for Linux kernel work has ensured a sizeable number of people are going to have to use it, whether they like it or not.