The term “trigger” in this context was initially used by mental health professionals in the context of setting off post-traumatic stress. I believe this here is

The term “trigger” in this context was initially used by mental health professionals in the context of setting off post-traumatic stress. I believe this here is an example of this primary (non-problematic) usage. It then got politicized and associated with “snowflakes”, and endlessly mocked and memed. Actually may be that more people know the word now from right-wing trash talk than from mental health concerns.