Also, for people who have experienced it, it's often the last thing they'd ever want to talk about. With anyone, including people they are really close to.
There's a good chance you could have a close personal friend or even your partner and never know they had gone through something like that.
These kinds of things fester in darkness and loneliness. I think bringing them out into the light where we can find out we're not alone is helping.
'Get over it' is the most common response. That's why they shut up about it. People who are close to them are only close because of something positive that is being offered. Nobody wants to deal with anyone else's issues.
I knew someone that was abused as a child. Had trouble with drugs and went into rehab. He said that ALL the people he met in rehab had been abused.
His offhand theory is that the increase in the prevalence of restaurants and hyperpalatable foods gave people an outlet to feel safe (a third place in public where the whole family goes and acts their best) and the hyperpalatable food gave an easy and cheap dopamine boost during hard times leading to a spiral.
https://www.ncbi.nlm.nih.gov/books/NBK201120/ search for "Evidence for a Decline in Physical and Sexual Abuse"
(searched for that to post this, and they cite %60 since the 1990s).
Freud himself discovered a tremendous amount of horrible abuse in his patients; depending on the culture, most people just turn a blind eye. People that haven't experienced it and recovered from it a bit are really good at not believing how common it is.