Consider the home life of a child. A child whose home life is abusive and chaotic would rather spend make-up time after school with a supportive teacher, going over the homework assignment, than trying to complete the assignment at home.
Parents, especially who were educated in third world countries where education is not seen as important, have to learn about the process and expectation of education in this country. You don’t coach them via ridicule and disrespect.
Then there are parents that are truly stupid and/or insane and that is hopeless for the child. The same goes for teachers and public schools. Sometimes the “professionals” are stupid and mean. Sometimes the whole school is twisted.