Tough math teachers get lower ratings from students, because students like them less. However, students get better grades with the tough teachers than with laxer teachers. Reason #167 why student evaluations of teaching aren’t particularly useful.
https://www.stevestewartwilliams.com/p/implicit-bias-training-the-psychology
Lol, only tough (brutal) teachers get good ratings with an unconditional support from parents.
This is why, for all its faults, I do support standardized testing. Without standardized testing, every incentive is for teachers to go easy on the students. Easier for the teacher, easier for the students, bad for learning.