Three comments:
1. That comic makes no sense whatever... but I guess that was the idea?
2. I have
no idea what the point of the "left-handed mouse" thing is. It's just as easy to use a normal, non-switched mouse with your left hand (as I do, and I
work in computer graphics).
3. Drawing with the mouse takes practice, though. If you're frustrated, and feel like spending money, try a graphics tablet. A lot of artists use them (but not me, so I can't recommend a brand).