As a graduate student, I often discuss the performance and abilities of undergraduates in very frank terms with fellow graduate students. However, I would never do so in front of other undergraduates. To do so seems clearly unprofessional. My question is, should faculty members have the same code of conduct towards graduate students? Is it inappropriate for a professor to discuss negative intellectual or personal qualities of their graduate students in front of other graduate students? I ask because a faculty member at my institution routinely criticizes the abilities and progress of one of their students in front of other students. I wonder if someone should have a discussion with the faculty member to stop this behavior.
Note: I can imagine scenarios in which it is appropriate for a professor to speak frankly, in confidence, with one student about another student's abilities, for example if students are having issues working with each other or there are concerns about the quality of work. But this is not what I'm talking about. To give a specific example, imagine a faculty member at a dinner with several other faculty and students, and loudly saying things like "Johnny can't even come up with testable hypothesis", "I'm probably just going to have to hand him a project", and "he'll get his PhD but he won't be successful in academia."
The answer to your two question are: YES! - Faculty members should have the same code of conduct towards graduate students? Why should an undergrad be treated with any less (or more) respect than a grad student.
NO! It is not appropriate for a professor to discuss negative intellectual or personal qualities of their graduate students in front of other graduate students?
This all falls under the realm of basic human decency.