While I initially sided with the professor (especially seeing the department's policies for class attendance), I see what you're saying and agree that public humiliation is more on the side of assholery, if you will. I guess perhaps I meet halfway between agreeing with this professor and agreeing with you; where the student really went wrong was with e-mailing the teacher in this manner, and perhaps that's why the professor responded with such a strong reaction (and forwarded it on to other students).

I will absolutely disagree, though, that it's a "worldly and wise" thing to understand and know class policy. He's chewing him/her out over established, known policies. In the "real world" - or whatever you'd like to call it - I, nor you, really expect people to need to have their hands held about simple policies, do we?