Y-axis need to start at zero when the data being presented is a bar graph and the bar is filled in. If it is a scatter plot with points being plotted, then it's generally not misleading to shift the axis.
I don't disagree with that - a bar chart that doesn't start at zero can be misleading. But for what he was trying to do---compare means---it would have been a perfectly fine choice to do a lineplot/very thin bar plot and start the y-axes somewhere other than zero if he included error bars and clearly labeled things.
http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0...