The problem is, he wrote that email from an emotional, not a professional level. He is clearly very frustrated with this student, and it is an on-going frustration, not simply an immediate frustration.
I understand his position, but yes, he wrote the email in a non-professional way. It is laced with emotion at every turn, and he is so emotional about it, he didn't even bother to check his grammer.
Both sides have a case on this one.
The moral of the story? Never let emotion interfere with your work. If you are ticked off, do not do anything till you calm down a bit. Then you can attack the problem from a more logical perspective and not an emotional one.
-S
__________________
 
|