A good software developer has to have reasonable people skills in order to write good code. Other developers will be using their code in the future, and good communication skills equate to well written and understandable code. As a developer myself, it's always a dead giveaway for the incompetent, in my opinion. Bad programmers think that mistakes that the user makes are the user's fault but in general, it's that they've written the software so poorly in the first place. I think that it boils down to that the exclamations are just a form of yelling and obnoxious condescension towards the user.
Exclamations show a real propensity for blaming others for one's own incompetence.
All rights reserved.