I'm not sure why people are trying to act like disorders don't affect your behavior. They literally do, that's why they're disorders. If the disorder didn't result in specific negative behaviors (in the absence of treatment or coping strategies), it wouldn't have been identified and none of us would be talking about it.
This isn't just something I've seen with borderline personality disorder, it's an attitude I've seen toward mental health struggles in general. I get that people are trying to reduce the pathological level of stigma we have in our society towards anyone with any mental health issues. We've seen it in this topic, people have talked about people with BPD in a way that you can't really talk about any other group of people. But it's counterproductive because it kind of implicitly concedes that if you have a mental illness that raises the likelihood of you doing X and you at any point do X, then maybe you're unworthy after all.
BPD is an illness that specifically creates a greatly increased risk of volatile and abusive relationships. That has to be acknowledged and accepted up front so that people with that diagnosis can be accepted for the human beings they are, accommodated, helped, and loved.
Once that is acknowledged, it has to be understood that these bad outcomes are by no means guaranteed. You may have met multiple people with BPD that is mild or that they are actively working to control. It is never acceptable to categorically discriminate against a group of people, unless there is a 1:1 ratio between that group's behavior and their membership in the group. It is just as unacceptable to compare human beings with agency and the potential for change to bullets, trains, animals, and other dehumanizing and destructive things.
Thank you, this is the more moderate and nuanced view that I was attempting to take, but you said it better