I am concerned that by being too accommodating to those with mental health issues, we are instead normalizing mental weakness. It's a difficult line to draw, because mental issues are not as easily tested by means of physical indicators, only behavioral, and behaviors can be faked or (more likely) conditioned by the environment.

I don't know what the right balance is, but if you were to ask me which side of the hill American universities are on, it's that they're being too accommodating, and that students should be expected, by default, to be tough enough to engage with difficult material.

Thus, the expectation should be that there is no need for trigger warnings. If a student really thinks they're unable to cope with some material, the burden should be on them to work something out with the professor. The burden should not be on the university to shield students from encountering challenging material.