I think what I took away from it is this: If I don't do starters I need to aerate for certain; and if I do a starter I will still aerate but I'm not going to worry about it as much, i.e. not wreck my back shaking the carboy. (I always do starters)
I would also agree that this was a single experiment and it is difficult to take it as fact; however, given what we know about yeast and why and when oxygen is important, the results are not surprising but reassuring.
It's slightly more complicated. In essence common belief is that any liquid yeast, starter or not, aeration is recommended. The oxygen helps the yeast prepare for reproduction, which they do when there is oxygen available (Actually they do *more* reproduction when there is oxygen present. They actually both reproduce AND ferment with oxygen, it's not an all or nothing thing.)
With Dry yeast the yeast have prepared themselves during the drying stage and are ready to go.
With that said, I generally aerate when using dry yeast if I'm not pitching a lot more than recommended rates (like using 2 packets for a mid range beer), or if the beer is just a big beer, like 1.080.
In any case, aeration is not going to HURT the beer as long as it's done prior to fermentation as the yeast WILL use up the oxygen and fermentation will drive the O2 out of the wort/beer. If added too late, some residual O2 may remain in the beer to oxidize it.
Not aerating under certain circumstances may lead to underattenuation, or possibly certain flavor characteristics depending on the recipe and strain of yeast used, etc.
It's just one of many variables to consider when brewing beer and there are a couple that are MUCH more important to beer quality IMO, such as pitching rate, fermentation temperature, sanitation, and even recipe formulation. That is not to say that a conscientious brewer isn't thinking about it, but when considering the odds, not aerating has lower potential for causing a noticeable problem with the final beer than some other things.
