Responses
I never had art profs that would tear into a piece or insult a student... thats what the other students are for.
I think it's *extremely* unrealistic to not critique the bottom 50% of the class- A) those students need the most feedback, B) the 'top of the class' crits are boring as hell (yay, you did a good job, keep it up...), and C) if you're spending 5 hours on a sketch, you could have spent 4 hours on that sketch and had plenty of time to address everyone's work.
Those kinds of art teachers are the fucking worst. I had a professor like that and I don't know how to explain that mindset other than "holier than thou" and think being bluntly honest is a positive personality trait when its really not caring about people's feelings. There's ways to say things without being a total prick about it.