1) You screwed up really hard and management wants to make sure you understand that and not to repeat it. This has been happening for a few times and you received an email without red/all caps before. If you were lucky, management even talked to you in person!
2) Your upper management is unstable, thinks they are superior in some way and basically doesn't care about people in general.
In any case, I don't see how this is effective (unless they want to push you to find a better place, which I would do).
I know for me personally sometimes I do dumb stuff and could use an email like that.