Snobby teachers can be socially immature, often have issues of their own crowding their focus, have been brought up to think students are to be herded, were sometimes attracted to teach for a power kick, are concealing incompetence and on it goes. School is not a market driven institution so poor performance can remain hidden for years.
Teachers are not your friends. They are there to help you learn and thanks to too many people accusing teachers of some things whether they did it or not they have to keep a wall around themselves to protect themselves from some brat who fails because they didn't put the time and effort in and then reports the teacher of some inappropriate behavior. Granted there are times it needs to be reported but there have been many that were just lies and ruined the teacher's career thru innuendo and rumors.
I'm sorry that so many people hate teachers so much, especially English teachers. One problem is that most teachers come from stable, loving homes and were successful all through school -- every grade, so they decided to stay in the school environment because they were successful there. Most teachers don't know anything else. They don't know the impact of poverty on learning and success. They don't know the consequences of a violent, chaotic home life on a child's performance in school. They don't know how it feels to go three days without food and be expected to be reasonable in class. Most teachers have zero knowledge or respect for the trades. They don't understand what is behind attitude and bad behaviour, and they aren't interested anyway. They relate best to students who are just like them, leaving a whole bunch of kids to get through a dismal system on their own.
Because nowadays kids do not care about their education and the parents think of the teachers as free babysitters. Plus the parents get mad if the teacher puts their kid in detention, even if the kid got detention for punching another kid in the mouth.