Instead of all caps and red maybe gentle and instructive works better.
A newcomer in the community broke an unwritten rule or an employee committed a company culture taboo? Did someone use a favorite cup in the break room cupboard.
Maybe the opposite of what we feel like doing in the moment would work better. Did they ever get the right instruction? Was it included in the manual?
How often do others respond this way? Is this a venting because something else happened?
Look back at the times all caps were issued. Did they get the results the writer hoped? Likely an email, whiteboard message or voicemail resulted in the target being shamed, catching the anger or worse yet gave up trying. If they did comply it was probably out of fear.