An argument broke out on a mostly British World War One group that I follow in the wake of someone posting a picture of Sir Douglas Haig, the British commander through the latter part of the war. Haig had been a big booster of veterans groups and veterans welfare after the war, and hundreds of thousands of veterans turned out for his funeral.
But this isn't a World War One post. What I thought was interesting is the structure of the argument that broke out among members of the group, which went roughly like this:
A: Hundreds of thousands of veterans turned out for the funeral of the general they respected.
B: My grandfather and great uncle both fought in the war and they wouldn't even join the British Legion because they said it was Haig's group. They loathed Haig.
C: As B's point underlines, Haig was a butcher and soldiers hated him for wasting lives.
This went on for many rounds, but of course, none of these contradict one another. It's entirely possible that hundreds of thousands of veterans respected Haig, while others hated him because they perceived him as a butcher who wasted lives. However, people have a tendency to think of groups, particularly groups with some kind of unifying visible "otherness" as monolithic: Soldiers think that... Police think that... Jews think that... Women think that... Latinos think that...
There are some common experiences which nearly all members of a visible group will have in common. Basically all Blacks (and most people who look strongly Hispanic, in areas of the country where there's a large, poor Hispanic population) have had some kind of experience of being treated with suspicion by police and others in a way that those of us who "look respectable" seldom do. Police all have the experience of being called in to deal with the sort of situations that most of us virtually never see, and also the experience of being treated like police (and the different things that means to different segments of society.)
However, even given these basic commonalities within a group, it's a huge mistake to believe that everyone has the same experiences in total, the same reactions to them or the same beliefs. Assuming that people's beliefs are fully determined by their group membership is treating them as if they are not really people at all, but rather projections of the group. That doesn't mean that group membership means nothing. It does often serve as a marker for certain shared experiences which can be powerful shapers of beliefs. But people still respond to those experiences in their own different and individual ways.