To some, this is probably very old hat. To others, it might be new. I am articulating it so as to remember it myself, because I think it is a good way of grounding knowledge in the absence of more solid data.
This is an observation - a learning without anything really solid underpinning it. But I think it is true, and therefore I will write it down. The observation is this:
1. When individuals or large masses of people complain about or conversely like something, it is for a reason.
And the more important corollary,
2. The reason is not always the reason stated.
Now; while this may seem like a simple observation, it has one very useful immediate consequence - namely, that whenever we observe a social movement, it is never without reason. It follows that it is never logical to dismiss the opinion of any group - no matter how seemingly stupid or irrational from our point of view - because their behaviour is for a reason, making it fundamentally rational given its premises. The tricky thing is figuring out what those premises are.
Consequence of this point: If tens of thousands of people are upset about something, there is a problem somewhere. There is never no problem. Nor is the problem ever trivial, or they wouldn't be this upset. If I insult a book, I can inflame hundreds of thousands of fans to come after me - but not for the trivial reason of the book itself. If people are willing to go to war over a book, it means something more to them than just the information contained within. It is in some sense personal - representing community, power, self-worth or any number of things. It wouldn't do this without some sort of historical context around it because the action of latching onto the book so hard is itself not without reason.
Grand sweeping trends do not come out of nowhere; and the only way to change the turn of the behaviour is to address the root of the problem. If people are angry, and you know why they are angry, the problem is fixable. If you do not know why, it likely isn't.