That is an appeal to tradition, and it a fallacy. It isn't moral for advertisers to do harmful things to users just because most advertisers do it.
Most scientist do not do harmful things to their subjects. Modern science requires consent. So your fallacious argument, even if it weren't, fails to argue correctly in the first place, because scientists aren't advertisers.
Facebook study was done without consent. It was harmful to their users (subjects) because it interfered with their emotions. It is immoral.
The outrage might seem ridiculous, from the perspective of an advertiser, because, as you said, they do worst things all the time, so this study is hardly appalling for them. But from the perspective of other people, it is.
I hope this gave you an insight into (our) reaction to the study.
Most scientist do not do harmful things to their subjects. Modern science requires consent. So your fallacious argument, even if it weren't, fails to argue correctly in the first place, because scientists aren't advertisers.
Facebook study was done without consent. It was harmful to their users (subjects) because it interfered with their emotions. It is immoral.
The outrage might seem ridiculous, from the perspective of an advertiser, because, as you said, they do worst things all the time, so this study is hardly appalling for them. But from the perspective of other people, it is.
I hope this gave you an insight into (our) reaction to the study.