On social media, the transactional nature of celebrity activism is sharpened. Ms. Portman joined Instagram on New Year’s Day in order to promote Time’s Up, submitting herself to the expectations of modern-celebrity ultra-accessibility for the cause. She followed a few dozen users: fellow activist-actresses, her husband and a suite of Dior accounts. By elevating Dior to that echelon, Ms. Portman ensured a space for the brand’s commentary just under a Time’s Up post: “Dearest Natalie, we are proud to have had the opportunity to partner with you to show our support for the #TimesUp Legal Defense Fund by making your dress.” Nicole Kidman also joined Instagram in the midst of the campaign — the platform itself announced her debut in a news release — and her first photograph promoted her Golden Globes win, #TimesUp and Instagram itself, all at the same time.

Watching this sparkling protest unfold, it’s easy to forget what exactly is being protested. The ugliness of rape and abuse is polished into optimistic hashtags and spun into glamorous dresses. In glad-handing Hollywood, criticizing the industry is verboten, but using one’s platform to advocate for other people is so expected it’s a cliché. (Mr. Weinstein himself was a master of linking his films to social causes, cynically pitching the award show ballot as a kind of morality test.) In focusing the messaging of Time’s Up outward — as a campaign to end sexual harassment in all workplaces — actresses have stepped into a quite traditional role, actually, of the celebrity who is both superficially appealing and actually deep, an icon of beauty and virtue.

The campaign’s goal to extend protections to working-class women is admirable. But it’s canny, too: Turning the focus away from Hollywood makes Hollywood a lot more comfortable with the inquiry. It leaves an opening for the industry’s response to the reckoning to also be a dodge. The most electrifying moments of this protest have come when Hollywood women choose instead to model what it looks like to interrogate their own industry’s destructive norms: When Debra Messing broke red carpet geniality to speak out against E!’s underpayment of women, straight into an E! microphone, or when Ms. Portman presented the Golden Globes’ best director nominees as “all-male.”