It’s a bit belated to write something about #BlackLivesMatter. Although the timing isn’t exactly intentional, I would half-justify my non-blogging by arguing that “now”—as in, “late”—is the perfect time to say something, precisely to make a small contribution to this issue not simply fading away (again) or to continue my own attempts to be something better than a just-occasional ally.

I have nothing to say about the issue of policy violence against black people itself—try reading some bloggers of color?—but I do want to vent a bit of sociologically-inflected annoyance at some of my white friends. As much as I’ve thought this is a minimally-demanding cause we can all get behind, I’ve had repeated rejections of my requests that others join me in walking in the streets for an hour or so to help elevate the voices of people of color.

The reason—that is, the articulated reason, which I’ll charitably say is not just a cover for racism—which I’m frequently hearing from my liberal-but-not-quite-left friends is that the movement is just not quite to their liking. They’d like demonstrations, but without the broken windows. They’d like people to shout “Black Lives Matter” but to refrain from “Black Power.” They’d join if only there was an a clearer structure, a well-articulated list of achievable demands, a leadership hierarchy.

Of all the concepts I taught last semester, Durkheim’s notion of “social facts” was probably the most important. It’s a simple idea: that there are institutions and patterns of behavior outside of us that constrain our actions and exist independently of anyone’s volition. But it was tough for my students to grasp (and not just because, as a novice, I flubbed the explanation). The notion of “social facts” runs against the American ideal: that we are all free agents, constantly remaking the world around us according to our own preferences.

Maybe most left-of-center people would accept that institutionalized racism, police lynching, and white privilege are “social facts” of American society. Yet when it comes to social movements, they imagine that we can—and should—only participate when things are exactly to our liking. I’ve received more than one message with a laundry list of things that the movement should do—advice about tactics, structure, and demands—that seem to suggest that people think there is some secret cabal that actually designs these things, and that, if they expect people to join in, they should design things better.

The reality, of course, is that big movements with the capacity to change society never really reflect anyone’s preferences. Instead, those movements are products of the very societies they are trying to change, and they embody their pathologies. #BlackLivesMatter has people who break windows because our political system has made people disillusioned with non-violent protest. It has clueless white allies because internalized racism doesn’t disappear overnight. It has the occasional outlier who takes the rhetoric too seriously and kills someone—because our society produces marginalized men, empowers them with gun ownership, and provides a ready stock of models for violent lashing out through such respectable channels as the Tea Party and radical environmentalism.

What I mean to say is: people want their movements a la carte, but reality is a bit more like a set menu. While those inside movements can try to push them one way or another, ultimately most of us have to make the simple decision of whether we’re on board with the movement—flaws and all—or not. And if you choose “not,” you don’t get to take society a la carte either: the fact that you’d prefer a world without police violence against black people doesn’t matter unless you’re willing to act to make it so, and, despite our post-modern conception of politics as self-realization, “acting” still means aligning yourself with some collective, assuredly imperfect vehicle for change.

Now, admittedly, our expectations for widespread participation in any movement should be incredibly low. Even in revolutions, most people sit out (yesterday’s demonstrations in France captured an eye-popping 5% of the population… which was still fewer than attended world cup celebrations). Even at the height of the civil rights movement, most whites thought blacks were pushing change too hard and too fast. When people tell me they’ll plug into the issue when Martin Luther King Jr. appears, resurrected, riding a peace-loving unicorn and leading a rainbow coalition of well-behaved rhetorically-measured activists, they’re admitting—knowingly or not—that all things considered, they’d rather just leave things as they are.

I tend to get labeled as overly black and white about these things: are you in or are you out? But in truth, it’s the people who expect movements to be flawless before they lend their support who are moral perfectionist. I actually get that both movements and societies are both shades of grey; it’s just that I want people to choose between the hues.