The term "malignant medical school" is definitely a new one for me, as I usually have heard malignancy used for describing residency programs where residents have an incredible amount of work - which may turn out unhappy individuals that are more interested in getting their work done versus entertaining medical students. However, it makes sense that some medical schools are malignant, as you may go to interviews and sense (or hear) from first and second years that their lives are completely miserable and they have to rely on tactics of secrecy and deceit to "get by" (I do distinctly remember this feeling at one interview several years ago). Luckily, I don't think there are too many schools out there like this (but I could be wrong) - but this does not have to be the case.
Yes, in some departments at most schools (as people have mentioned) - there are people who essentially live for embarrassing medical students - but I have yet to experience this. I have personally encountered people who begin as very intimidating or harsh in their approach, but eventually, they turn out to be some of best teachers after the "getting to know you" period. Rarely have I remained in a so-called "malignant" relationship with someone for a long period of time (i.e., the duration of the 4 or 8 week rotation). In general, as long as you put in a good effort and essentially show that you are trying to think through a problem versus always saying "I don't know", people are willing to work with you if they see that you are willing to learn. But there are some people who are who they are, and for some reason (e.g., whether due to respect, tenure, etc.) never change and gain the reputation of not being medical student friendly.
If anything, the people who are most in jeopardy of being more "embarrassed" per se or more heavily judged are residents - and this has been most pronounced in surgery. But a part of this seems to be a method of teaching, not through intimidation, but through the idea that you will not assimilate information if no one asks you questions about what you have read and have supposedly learned. However, there is definitely a way to do this without crucifying or being rude to people.
The moral of the story is that, at this stage in the game, you should concentrate on what will make you happy at a medical school - including your feeling about the interview and your interactions with medical students, location, curriculum, maintenance of "self" (a very important yet often forgotten aspect), research and extra-curricular opportunities, etc. Yes, you will likely encounter some not so nice people, but no medical school should be [openly] popularizing mistreatment of their students - or they wouldn't have survived very long as an institution. As previously mentioned, be proactive about talking to medical students at several levels, both pre-clinical and clinical (if possible), before making a decision based on the experiences of one. Assess how you would fit at an institution based on a number of factors important to you, and you are more likely to find yourself in a place where you can "enjoy" your education (as much as this "process" of becoming a physician can be "enjoyed" - because you are not always going to be at the pinnacle of happiness in medical school or in practice as a doctor).
Best,
H&T