1. As far as human nature is concerned
People are emotional creatures, and teachers are just ordinary people, with feelings, values, and their own style and bias. No one can remain absolutely rational and have no personal emotions in all situations, but as a teacher, his job is to teach and educate people. It is understandable to have personal emotions in the process of educating students, but the foothold of everything should be that this emotion will not be conducive to the subsequent development and cultivation of this student. Even if we can't achieve absolute rationality, we can still rely on rationality to control our sensibility within a certain reasonable range.
From my personal experience.
Because I don't know much about the case of Tongji, I'll talk about my personal experience. My childhood education experience has also made me know many teachers. The teaching styles of these teachers are more or less related to my personality and mood, or vigorous, rigid and strict, or lively and gentle. However, I still feel that as long as this kind of emotion does not have too great an impact on the quality of education and students, it is within the understandable range.
Finally, I want to say that perhaps as a student, it is an ideal appeal to yearn for a teacher who has no personal feelings at all. But there are indeed good teachers who are positive and full of ambition to teach and educate people, even if they are mixed with personal emotions. Emotion itself is not a derogatory term, the key lies in people's control and utilization of it.