You might have missed the irony.

If so, it would be easy to understand. Last week’s bulletin about accused serial rapist Bill Cosby was sensational enough that one might be forgiven for failing to notice one of its more subtle facets.

As you no doubt already know, a federal judge sided with the Associated Press, which had sought release of a deposition in a 2005 civil case brought against Cosby by a woman named Andrea Constand who accused him of drugging and sexually assaulting her. In his sworn testimony, he admitted to obtaining seven prescriptions for Quaaludes in the 1970s, with the intention of giving them to women he wanted to have sex with.

Cosby’s lawyers would not allow him to answer the obvious follow-up question: whether these women were drugged without their knowledge. And here, let us duly note that he has never been arrested for rape, much less charged.

But given that dozens of women have now accused Cosby of doping them and having sex with them without consent, the admission that became public last week seems the very definition of the old axiom about smoke and fire. It is not the final nail in the coffin of his respectability; that was hammered months ago. Rather, it is the foot kicking that coffin off a high peak, down a bumpy mountain into rushing water bound for the sea. And it paints as delusional that dwindling corps of true believers — looking at you, Whoopi Goldberg — who insist there is still some path to vindication for the once-beloved comic who brought us Alexander Scott, Fat Albert, Cliff Huxtable and Little Bill.

Yes, it’s fair to say Cosby wouldn’t be in trouble in the first place if he’d done a better job managing “Little Bill,” but that’s not the irony alluded to above. Rather, it is the reasoning Judge Eduardo Robreno gave for allowing the release of the deposition. He wrote, “The stark contrast between Bill Cosby, the public moralist, and Bill Cosby, the subject of serious allegations concerning improper (and perhaps criminal) conduct, is a matter to which the AP — and by extension the public — has a significant interest.”

In other words, had Cosby not spent so much time exhorting other people to do right, we might not now be privy to evidence of him doing monstrously wrong.

That laughter you hear is from some in the African-American underclass who were the most frequent targets of Cosby’s moralizing. He commanded them to be better parents, discipline their kids, stress education and pull their pants up on their backsides. The view from this corner was — and still is — that Cosby’s harangues were often ill-tempered and overly broad, but that they nevertheless spoke a valuable truth: African-American people need to be agents of African-American uplift.

Cosby will never again have the authority to deliver that message. And therein lies one of the great tragedies of this affair. A thing that needs saying has one less voice to say it. Nobody asked him to be a public moralist; he could have just told jokes, collected his pay and gone home. That’s what Chris Rock and Jerry Seinfeld do, and it seems to have worked out fine for them.

If you’re going to be a public moralist, you accept a moral obligation: Be what you said you were. You don’t have to be perfect; perfection is not within the human repertoire. But there is a vast gulf between “not perfect” and “accused serial rapist.” Cosby’s failure leaves his career, reputation and legacy in shambles — and increases cynicism in a nation where that quality is not in short supply. He has left us with one less repository for public trust.

People believed in this man, believed in his integrity and goodness. And he played them — played us — for fools. After all, Cosby presumed to police America’s morality.

Apparently, he couldn’t even police his own.