I took a course in undergrad where the teacher demanded a very high amount of work and participation from everyone in the 60 person class, and while I was up for the challenge I struggled in the class the entire semester because of the balent favoritism. There was a small group of students who met with her weekly outside of class to study (this was not made avilable ot all students, just these few) and they received special attention in class as well, often being called on before other students (which greatly impacted our grade since we had to partipicate atleast once a week or we went down a letter grade). A few of us discussed this with the professor, to no avail, and I lost all interest in the class about half way through since I realized she didn’t really care about any of us except these few students.
To fix this situation the goal of the teacher has to be to teach all the students, to give them all a chance to learn and participate, always calling on the same three people does not promote an environment whre everyone feels valued and heard. It makes it difficult to justify asking questions or actively participating in the course.