So, it isn't the soda causing the aggression, it's the environment that allows for children to access and consume a large amount of soda that causes a child to be aggressive? That appears to be what you are saying here anyway. If so, how can that be when the study makes this far fetched claim?
If they controlled for all of these variables, then it has to be the soda causing the aggression, right? Just my humble opinion, but it appears that these researchers have created the desired results to keep the public alarmed and the grant money flowing. There's a lot of that going on out there these days.
Far too many of these people are trying to sell correlations as causes, and there are even more people buying into this nonsense. When I was in school, there was a book published offering all sorts of wacky correlations. The book showed, conclusively, that the price of peanuts in Georgia could be determined by the amount of rainfall in Fiji. They had the statistics to prove it, but I hope no one believed it.
95% of all research ends up being meaningless. It's the nature of research. Unfortunately, there is more junk research being done these days because of the need to produce grant money. To your point, there is very little information included in this story. However, research like this today is is rife with highly flawed studies, data dredging, flagrant misdiagnoses, and all kinds of tests that provide misleading results. The tiny amount of information offered in the article, at least for me, makes it pretty obvious that this is just more junk. But I'm sure it will deliver the money from the NAS these folks desire so they can spend their time in the lab rather than actually having to teach.