The fact is that many, if not most, of the students in a college classroom will be unaffected by the course material that could be potentially triggering to people. However, providing trigger warnings allows students who would be upset the opportunity to either prepare themselves mentally or else just not take the class. Providing trigger warnings is less of a hassle than dealing with lawsuits from offended students.
It's really not too much trouble to warn people of possible triggering beforehand. I don't understand the outrage over trigger warnings and things of that nature. It basically has no effect on anyone, except for those who have PTSD and might be affected by something. I don't think that professors should be required to do it, but they should at least make an effort.
Trigger warnings should not be necessary in a classroom that consists of adults. In colleges, you are not dealing with kids, you are dealing with adults who are going to have to see uncomfortable things in the real world. We need to stop coddling people and let them grow up.
Trigger warnings are the result of an out of control outrage culture that prioritizes emotions over reason and common sense. College is a place to grow as a person and to expand one's mind and learn new ideas, not a rubber room carefully designed so that one ever has to face an idea that might make them vaguely uncomfortable. Trigger warnings encourage emotional immaturity and discourage critical thinking, which are exactly the two things a college should NOT be doing. If we allow people to insulate themselves from new ideas, to hamper and hinder their own critical thinking, and to hide behind perceived emotional distress, we are doing both our students and our society an immense disservice.