i feel that perhaps being a good person, or being there to support others is about accepting when you don't know what to do, and learning...and maybe they have too much going on to be able to...But, I think too many times, people are just not willing to stop and help a friend.
I think that it is not often about people not being willing to stop and help a friend. I feel it is important to not take this personally and to not feel rejected. People are who they are - flawed, silly, unaware, out of their depth and sometimes just busy in their own lives.
Helping a friend is more simple than dealing with high level PTSD distress though. I think we need to be clear about that. Otherwise we have child-parent expectations of the people around us and that sets us up to feel unhappy about ourselves.
People, also, on the other hand, are not counsellors, psychologists or psychriatrists. And I know how hard it is when you want to talk to someone and reach out and there is no one to listen or be there for or with you. That is tough. However, there are some things which are not appropriate for friendship and which are unreasonable to expect people to listen to or understand. Professionals are all in debriefing groups and supervision - some of them - on top of having studied for 12 years. So it is not surprising that people in general can't cope with PTSD or child sexual abuse or the rest of it. How do they manage all those feelings of powerlessness and sadness and overwhelm, which even professionals find difficult to deal with.
I would suggest that taking someone's inability or unwillingness to listen to you - not as a rejection - not as a snub, even that is one way to read it. It could also be that they recognise what you are going through is so serious that they don't want to get in the way of someone who could really help you. So it could be a honest caring response as well.
With the hyperviligiance of PTSD it is hard not to be paranoid - it becomes hardwired in to us - but it is important to sometimes float other ideas and theories to enlarge our thinking processes and our ways of seeing ourselves and people in our lives.
I try not to listen to people any more because I have so much on my own plate. I also don't have the skills that are necessary for some situations. I am, myself, just getting though the day.
Also one thing that I have noticed, after a lifetime of listening to people is that if you do this then they stop treating you like a friend. You don't get invited out. You don't stay as part of the friendship network. You are the "support" person. That is not a fun position to be in either. So there are many layers to it. The obvious one to our PTSD minds is that no one cares, or we are being rejected and so forth. But this might not be so.