What is a good explaination of this quote?

Shouldn't that be "Teachers may have overcrowded clrooms and lack resources such as counselors to ist with particularly disruptive students or clroom dynamics”? That would make sense if "et" was changed to "ist". Then it means that teachers have too many students to be able to give them the attention necessary to instruct the cl properly and deal with problem students, and have nobody to help them in this. If the number of students a teacher has is more than they can give individual attention to, then they have too many students. If they have nobody to help them, then any problems which arise are difficult to deal with and create more of a problem for the teacher to teach and the students to learn.