I think the core issue with your response is, unless the project in question
is the "conventional tools", why do you seem to think knowing those tools is even germane to the quality of someone's contributions?
I write python and some C++ stuff for fun in my free time. If your project interests me, but I have to spend said free time to learn esoteric tools to interact with it that aren't needed elsewhere in my life, how do you figure that's valid?
It's not that I couldn't learn to deal with that kind of shit, it's that I don't see why I should bother. If everything else works without e-mailed diffs, all that does is make anyone with more then one hobby project do is look elsewhere.