I have a hard time believing that isn't a troll.
A phrase posted at the beginning of various posts, articles, or blogs. Its purpose is to warn weak minded people who are easily offended that they might find what is being posted offensive in some way due to its content, causing them to overreact or otherwise start acting like a dipshit. Popular on reddit SRS or other places that social justice warriors like to hang out.
That's the Urban Dictionary definition for it, and I think that's generally accepted here. That line of thinking marginalizes victims of sexual assault, war experiences, rape, suicide attempts, psychological torture, etc. who actually
need
trigger warnings.
Imagine you were abused as a child -- raped, sexually assaulted, manipulated, beaten, whatever -- and you're someone who genuinely appreciates a warning that these topics are about to be discussed, to avoid a post-traumatic flashback or something similar. After all, having empathy for a victim like this is general decency, and a trigger warning takes two seconds to type.
Then you go on Reddit and see the "Its purpose is to warn weak minded people who are easily offended that they might find what is being posted offensive in some way due to its content" attitude towards trigger warnings, and Reddit making a mockery of trigger warnings in general. That's not a very inviting environment.
PS. Thanks for actually having a reasonable conversation with me. Much appreciated.