I gather that there's a backlash against trigger warnings going on. Rather than continue to have this argument every time someone I know posts a link about how obviously evil and stupid trigger warnings are, I'm just going to post my own statement here, so I can point to it later.
My own use of trigger warnings is in line with what I was always told was the point of them: letting people know ahead of time that there's something there that might be incredibly upsetting to them if they ran into it by surprise. When I post a trigger warning, I'm certainly not telling anyone to avoid reading what I'm linking to; I'm pretty sure that people read triggery stuff all the time, even after being warned. The warning is a friendly and sympathetic just-so-you'll-know, not a Keep Out sign.
Example from the other direction: Sometimes when I'm reading stuff online, I'm in a mental space where I'm fine with reading about (for example) people's parents being murdered. But sometimes (even though I don't have PTSD or flashbacks) I'm not in a space where I'm okay with reading about that kind of thing; and when I'm not, I'm glad when friends of mine look out for me by letting me know that there's a landmine ahead. That way I can come back to it later (if I want to) when I'm feeling stronger.