Let me just say this, however.
In the large state universities, a great deal of the teaching is done in Freshman and Sophomore classes by graduate teaching assistants who are inexperienced teachers. These TA's are often very young and often not very knowledgable. The training sessions for TA's are minimal.
Some of these young TA's are politically minded, mostly leftist (not all), and some think they are on a mission. It's with these young teachers that abuses can occur.
I have a great deal of experience in this environment, since I was a TA myself for a number of years. But the environment I was in was the liberal arts.