What It’s Like to Be a Diagnosed Narcissist

In other words, it makes them special, so they happily admit to it, because being special is exactly what they want.

Men interact based on boundaries and often hierarchies, and a guy who is obliviously transgressive to that is usually thought of as "on the spectrum," or more rarely, a narcissist. Sometimes they are in actual positions of competence or authority, where their lack of respect for personal boundaries is consistent with an externally granted authority role, and this misdirects from the more pathological aspect of their behavior. Being transgressive is sometimes a sign of exceptional intelligence as well, so people tolerate it under the aegis of "brilliant jerk."

Personally, I have some sympathy for them because it's such a steep hill to climb if they are going to ever improve, but have learned to just be unambiguous about setting boundaries and making it clear I think they have a blind spot on boundaries they need to manage.

Provided you aren't being paid to take their abuse, you can reasonably say to them, "Consider whether you may have a blind spot on personal boundaries." If you are being paid, I recommend getting paid somewhere else.

No. That's not how it works. Understanding a cause of a behavior is not the same as denying responsibility for the behavior. This sort of thinking is what leads to the (extremely flawed) conclusion of "I was abused, and I turned out okay, so your behavior because of your abuse was your decision" thinking.

What you're doing here is victim blaming. If someone abuses you, this is not your fault. If, because of this abuse, you have social problems you're still going to have to figure out a way to deal with these problems. Understanding the root cause of the behavior (ie; my mother molested me, thus I have a strange view of sexual norms, thus I engaged in abusive sexual behaviors) can help in the treatment of this behavior. In fact, I would go so far as to say that understanding the root cause is almost always needed in order to treat the behavior.

You make the extremely flawed assumption that by exploring an understanding of causation (abusive parent in this case) that the person in question is not working on fixing the flaws. These ideas aren't mutually exclusive. And for many people, groups, including reddit groups, act as a way to work through their problems with others capable of relating to their situation.

If someone's entire course of action is "my parent was abusive, so I'm going to keep engaging in this behavior because now I have an excuse" the problem present is this person's continued desire to behave poorly. It doesn't absolve the parent from their portion of creating the problem, nor does it absolve the person in question from engaging in the behavior.

Tl;dr- No, none of your points stand on their own.

My BPD stems from childhood abandonment (absent father) and persistent emotional abuse from my likely NPD mother. I learned to doubt things I feel/thought and often reality sometimes. Real love and emotion connection were terrifying to me on a subconscious level. I never could trust anyone, not even myself (the only one to trust was my abuser). I developed so many coping mechanisms to protect myself from my mother that involve projection, distortion of reality and emotional manipulation. My brain learned all these horrible ways of protect myself from my abuser and I applied those behaviors to everyone around me.

It has taken years of unpacking my childhood trauma to get to like 90% remission of symptoms. Before that it was years of denial about my behaviors before I even started to entertain the fact I had BPD.

I'm sorry to hear BPD is effecting both you and your brother. There is hope but he has to be on board and it's a long road.

Probably not a good idea, to self-diagnose online.