Why are they seen as bad people? Because people are not trained to separate behaviours/actions from the person doing harm. A child being hurt will think "It hurts. You are bad. I hate you." An adult being hurt will try to enforce some "socially accepted rules". Bad people break rules. A supporter being hurt accepts that the behaviour will repeat itself and sets boundaries. If the boundary is broken, who will be blamed? When we feel that we are being harmed, we do not stop to consider "Is this done with malicious intent or is it just a brainless script being acted out by a person that has no clue of the damage being done." All we feel is pain. Whatever my belief has been, I have failed to stop the pain felt.
I think that we need to own our own roles. Take manipulation for example: It is all around us and it does not need to be caused by someone with a mental disorder. Some of the manipulation is well intended. Some of it is not. It can be done by someone that is aware of it and it can be done by someone that is not. It feels ugly like someone is forcing you to do something you do not want to do. My job is to figure out if the person making demands has that authority. Without my permission or agreement, they don't get to make me do anything. In my experience, manipulation happens because I am afraid to loose a person, a financial advantage or a feeling of belonging. As long as I am willing to investigate my fears or cut my losses then I don't get manipulated. If you yell at me to get me to do what you want, I simply won't do it. Not everyone has the thick skin you need to have when in such a position.
When I am accused of manipulation, I really try to listen and understand why the person feels that way. I don't try to change their mind. Before recovering from my own issues, I was in too much pain to realize how I affected anyone. In my opinion, any interest in how others feel shows that you are on your way to a recovery. If they still feel manipulated then I don't insist on the relationship. It is a perception. Manipulation is hard to know or prove one way or another unless it has become a pattern. I know from personal experience how hard it is for anyone that feels manipulated to change their belief and to view things differently. Its a trust issue. I do not want to be in relationships where there is no trust.
We are living in a society where to "put our needs first" has become not just common place but makes healthy sense. Altruistic acts are often questioned. You become a suspect when no one can see the benefits you reap from self sacrafice.
BPD is poorly understood and the basket where all that lack of understanding gets dumped. By trying to understand it as best I could, I have grown tons and I have failed and then picked myself up and becomed more humble when it comes to dealing with pain..both that of others and the baggage I carry.