I think, in the past, social justice campaigners were challenged with singular, tokenistic exceptions. “Racial inequality!?” the old jingoistic buggers would bellow, “but there was a fighter pilot from Trinidad in the 2nd World War!”
To respond to this, we would point out that we were looking at a whole society. “There are always exceptions,” we’d retort, “the fact that there are so few of them proves our point – one, solitary pilot of colour!”
Once discriminatory legislation has been dismantled, some members of formerly marginalised groups will start to do better. However, these are outliers. We still need to tackle prejudice in social norms and narratives. Britain, with a history of democratic liberalism, condemns prejudice and discrimination, so everyone is very reluctant to admit to themselves that they entertain these biases.
So, evidence for such discrimination comes from looking at statistics. We were interested in the differences between subgroups in whole populations: it’s not that white kids aren’t stopped and searched, it’s that far more black kids are. There are thousands of black doctors in the UK, but far more white and Asian.
These discrepancies are highly significant. They attest to inequalities of opportunity and limiting of life choices. They suggest that many people will have been treated very badly due to assumptions made about them. However, the numbers come from enormous data sets, 60 million people, in the case of the UK alone, with multiple contributory factors, and thousands and thousands of exceptions.
Any monocausal explanation, any overarching grand-narrative, is going to be far too simplistic to fully explain the phenomena you’ve identified. But sophisticated analysis is laborious and tedious, and the equivocal conclusions it tends to throw up are complicated and unsatisfying. It’s far more fun to plough on with our preferred theory, ignoring and dismissing all anomalies, and using confirmation bias to seek out evidence that supports our claims.
Having come up with some totalising and easily graspable theory of everything, the temptation is to clutch it like a talisman, to brandish it like a weapon. Especially, for professional social commentators, if you gain a reputation for voicing these opinions articulately, if they become your USP in crowded market (although this can lead to annoying pigeon-holing.)
But then, ironically, you find yourself massively over-applying your theory, even making far-reaching and unfair assumptions about other people on little evidence, without considering other explanations or complicating factors. Without empathy or understanding. Like a racist.
 Afua Hirsch said recently that she’d had “literally hundreds of calls”, asking her to comment on Meghan Markle’s fight with The Palace (whoever they are!) (The Guardian, 05/03/21); Otegha Uwegba complains, understandably, about how “Black Writers [are] assigned the position of race educators whether they like it or not” (Whites: On Race and Other Falsehoods, 2020, London: 4th Estate, p25)