I understand your point, and it's a good one. But it seems to me that previous big innovations were qualitatively different from Di2. The freewheel, the derailleur, index shifting, clipless pedals, etc - there were mechanical improvements, and still relied on human power. With Di2, we're moving away from human power. Your point that with electronic shifting "information is transmitted in the form of bits rather than cable tension," seems hollow. You could apply the same principal, if taken to its logical end, to electronic pedaling.

I feel the need to repeat: I am not a technophobe, and I don't choose to arbitrarily (and hypocritically) draw the line of technological acceptability at electronic shifting. On the contrary - Di2 seems to be an interesting (even amazing) technology, and if folks want to use it to get around town, great. I simply think that, for the purpose of racing, Di2 fundamentally changes the definition of what a bicycle is (a purely human powered machine), and should therefore be rejected.