why didn't vulture say who spiderman was

The Vulture (Adrian Toomes) did not reveal Spider-Man's true identity because, after Spider-Man saved his life, Toomes felt gratitude and chose to protect him by keeping his identity secret. In the Marvel Cinematic Universe film "Spider-Man: Homecoming," Toomes is portrayed as a family man and a "regular guy" who doesn't have grand villainous ambitions but wants to protect his own family. This humanized portrayal explains why he refrains from divulging Spider-Man's identity even when asked while in prison. Toomes' motivation is to protect his family and avoid unnecessary harm, which aligns with his refusal to reveal Peter Parker as Spider-Man.