It’s no one’s fault if they have BPD. No question. Horribly unfair.

But untreated BPD symptoms can cause problems in relationships, obviously. (If it weren’t a problem, it wouldn’t be an issue requiring diagnosis.)

Other people aren’t in your head, they don’t know your background, they’re not psychic and most aren’t psychologists.

All they can experience is your (anyone’s) behaviour and how it affects them.

Unpredictable, impulsive behaviour, especially anger, destabilizes relationships. Because most people (including pwBPD) like the world and people in it to be predictable and reliable, safe and trustworthy.

And people have the right to decide if they’re willing or unwilling to put themselves, emotionally, in the hands of people who - while untreated - struggle to manage their emotions, act out, etc.

Whatever the cause of abuse is, when it happens, it’s still abuse. You can’t blame people for wanting to protect themselves.

Should there be more accessible treatment for pwBPD, absolutely, I would advocate for that 100%. In fact I think everyone, literally everyone, would benefit from DBT taught in schools, early on, too. It should be a required class, alongside math and English.