The jail also seemed to do a poor job of letting families know what was going on. Another woman, Isabel Vega, said she had grown worried about her husband in the middle of last week because she hadn’t heard from him. When she emailed the jail to voice a concern, she heard nothing back. It was through a post on Instagram that she was alerted to the prisoners’ miseries.

Others held at the detention center wondered why they were not moved to another building on the same block that was part of the facility. According to Arthur Aidala, a lawyer who was visiting one of several clients at the jail, this building had heat and power. It houses mostly female inmates on two floors but is otherwise empty, he said, and while it would have been logistically challenging to move so many inmates at once, the jail moves them back and forth to court all the time.

Why the building did not resort to generator power was also left unexplained. “Can you imagine if this were an apartment building on the Upper East Side?’’ Mr. Aidala said. “But here, you have to consider who the tenant is and who the landlord is.”

The landlord, of course, is the federal government, led by a president who, two years ago at a speech on Long Island, suggested that police officers should not bother to protect the heads of suspects as they put them in police cars. He was speaking to law enforcement officials, and he told them they could “take the hand off,” a comment that elicited cheers from the audience.

Without a big push on social media from influential activists — Tamika Mallory, co-president of the Women’s March, was one of the organizers of the protest that began over the weekend — it is hard to say how much emotion the power failure and heating issues at the jail would have unleashed. How much is ignored because it can’t be distilled to one and a half minutes of haunting footage? The images of inmates banging on windows had supplied that — the sense of something dark and medieval.

The same jail had, in fact, been hit with a series of sexual assault cases in recent years — female inmates had accused guards of molesting them — but there was no similar outcry. Hunger is a big problem in this country, but hunger isn’t visual; there is no clear path to Instagram.

The Metropolitan Detention Center also finds itself in a place that can no longer be considered remote. Gentrification has changed that.