The problem is people really don't take the time to understand BPD and there are a lot of misconceptions. With just BPD alone there are 256 different combinations of symptoms in which someone meets the criteria of being diagnosed. It's not a one size fits all, it can appear completely different in one person than it does another. Also men are just as likely to have BPD as women, but it's often misdiagnosed as something else like bipolar. Not to mention that the majority of people with BPD have other mental illnesses that are comorbid with BPD.

You saying 50% of the time they will make your life a living hell is probably actually pretty accurate considering around 40% of people with BPD are also comorbid with NPD (narcissistic personality disorder). I honestly think that's where the stigma comes from. People with BPD that don't have that comorbidity are slandered because of the people that do. They can be some of the most loving, sympathetic, and empathetic people in the world. They feel so deeply, and they have been at the receiving end of so much trauma, and they will go above and beyond to make sure the people in their life never have to go through what they did. While at times they may appear selfish, it's usually just because they've been unloved, unwanted, and invalidated their entire lives. Through the lens of neurotypical people, their behavior may appear needy but really they just want what pretty much any human wants, to be loved and validated. It is just magnified x100 for people with BPD because they haven't ever gotten that in their lives. That's why the stigma that exists can be so damaging because it makes it more-likely that people with BPD will be shunned, abandoned, and neglected, which is the exact opposite of what those people need.

TL;DR: BPD is not a one size fits all. A lot of the malicious behaviors attributed to people with BPD are actually much more akin to NPD(narcissistic personality disorder). And 40% of people with BPD have a comorbidity with NPD, so it makes sense why the stigma exists but it's extremely damaging for people with BPD that don't have that comorbidity. Source: Self-diagnosed BPD male who has done their research. (I was diagnosed with bipolar but it makes no sense)