It's not that nobody wants to hear it, most people who aren't trained listeners, counsellors, therapists etc are not equipped to support you with it. It can become too much for people and they may become overwhelmed by someone repeatedly talking about all the traumatic or upsetting things that have happened to them and/or their feelings about that. It can difficult for others to handle emotionally, particularly on repeat.
People can also become frustrated when someone is constantly bringing problems and will do nothing to change their situation, won't seek professional help, or sabotage every attempt at engaging with help. My grandma is like this, she wants help and says she doesn't have enough help, but won't say exactly what she needs, then nothing anybody offers is good enough for her and she gets angry and sends them away. It's exhausting constantly going through the cycle of being told x, y or z is a problem and is upsetting her, going through what could be done to help, then having her reject everything and then complain about getting no help/nobody wanting to help her. I'm not saying you do this exact thing OP, I'm using it as an example of the kind of pattern that can burn out the emotional capacity of loved ones very fast.
In general, most people like to be kind and helpful, and alleviate suffering where they can, because we like to feel like we are being effective and productive as humans. But when suffering is someone's entire life, and you feel there is nothing you could do that could possibly help them or be of use, except be talked at like a pot plant in the corner, people will begin to withdraw, unfortunately.