I feel the opposite way tbh. I feel bad for the student who gets this kind of rude feedback. That is, if it's even real. But teacher mentality like this def can be real either way. Like what kind of feedback is "horrible opening"? What is there to learn from there? Students are in classrooms to learn. If they were great at what they do already, there wouldn't be a point in them showing up. If somebody is significantly behind, that's what remedial programs are there for.