Do you mean, "you need not just suspect, I can confirm that in my experience at CMU the professor is over-credited", or "you need not be suspect, in my experience at CMU the credit is properly allocated"?
But given the thread root, and not knowing any more about Qz -- indeed being unable to trivially associate that handle with a real name/project via the profile page -- a cynical comment from a disgruntled grad couldn't be ruled out.