up in arms about (something)
Very upset or angry about something. Likened to an armed rebellion, from which the phrase originated. The whole town is up in arms about the addition of a new shopping center. Mom was really up in arms about the dent in her brand-new car.
up in arms about
protesting angrily about something. 1994 Asian Times A lack of checks and balances…or legal redress for workers have trade unions up in arms.