Maybe they are lonely and it is an excuse to just connect with others, and your kind response might keep them alive another day!
Maybe their mind is so boggled and they fear to make any change, they will never remember your words, but will remember the compassion felt if it is genuine.
I think that it's easier to put people on ignore if they don't make strides toward healing and you rather not waste time reading their posts.
If that is what is healthy for you, then that is what you should do. Many of us have issues with controlling situations or we feel frustration, that is about us, not the poster.
I know a poor man that works at a shelter and feeds homeless several times per week after working at his job with small pay. He confronted a couple who he knew for a fact stole his paycheck and cell phone, and most unable to afford to be robbed. Someone suggested banning the couple from services for a month, but he declined and continued to welcome them and feed them weekly. I was puzzled, he was much kinder that I could have been. 2 wks later, the phone and check were left exactly where they were taken from. He could have punished them and did not. The couple are in active addiction too. I pondered this in awe of his kindness in spite of being stolen from. I aspire to be like him, not even angry. Then it hit me. It is the true answer to "WHAT WOULD JESUS DO". Which of our sins is it that Jesus is unwilling to forgive.
When I feel I am being played, used , strung along, victim of attentions seeking , stole from,etc. I tend to become self protective and not want to be the chump here. I might become angry and frustrated.
Its really all about ego.
Depression can be paralyzing and debilitation. I cant compare my back pain with yours, my surgery was more extensive so why cant you get on with it. Maybe you have a lower threshold. We never really know what is in someone else. Some days, I cant respond. others I can. I try to only when it is genuine.
There is nothing so painful as to feel all alone in this world, with not one person to connect with. Feeling unconnected with life in any way. If someone needs a superficial topic to get some connection, I will try to help when I can. When my cup is not running over. Best I have is acceptance of myself and sorrow for other.