Retribution!
It was absolutely retribution! When Umbridge tried to blow up the radio, the collision between the Exploding Charm and the radio caused a violent blast that injured her. After she was carried into the School Hospital, students throughout the school cheered and celebrated.
As Gryffindor students asked around about the previous night's broadcast, news of the Wizard Lookout Station Broadcast spread among the students at an astonishing speed. Everyone was curious about the Pink Toad's old history.
According to information leaked by Hufflepuff students whose radios had not yet been confiscated, Umbridge actually had no connection whatsoever to the Selwyn family. Her father had never died, nor had he been some distinguished figure in the Wizengamot—Umbridge's father was Old Umbridge, a cleaner at the Ministry of Magic back in the day.
Once this came to light, everyone gained a new understanding of their High Inquisitor.
Although Hogwarts students did not feel as strongly about it as others did, Umbridge's string of outrageous antics still earned their contempt and disdain.
Of course, the information leaked by the Wizard Lookout Station went far beyond that. For example, the station had somehow found a group of people claiming to be Umbridge's former colleagues, who appeared as guests on the broadcast to expose all kinds of her Dark History.
Naturally, the so-called guests were fake, but the people themselves were real. They had even used Polyjuice Potion as disguises, leaving no flaws for anyone to find.
Sirius and Lupin's stunt was outrageously clever.
"Umbridge is exceptionally skilled at putting on a false front to curry favor with her superiors."
"Umbridge often ruthlessly steals the credit of other colleagues and claims it as her own."
Watching the excited Hufflepuff students chatter away without pause, many Gryffindor and Ravenclaw students regretted missing the radio broadcast.