You're brave, Billi, for putting yourself on the spot when you know there's more of a chance, or than not, that you're going to walk away feeling disrespected or not appreciated. I generally avoid situations like that. That is one way you're more "mature" than me...I still yell out or walk away when facing that type of situation. I've blown up on a class of students before who were ignoring me.
There must be something about people with BPD, (an invisible sign on our backs that everyone else can see that says "ignore me"), something about our speech, or body language, the way we present ourselves that we are not aware of that lead to being ignored, misunderstood, disrespected. Don't ask me what it is but I've been in that situation many times myself. Maybe watch other people when they talk. How to they present themselves, what do they say, or HOW do they say it that might influence how others react to them? Is there anything that they do that you (we) don't? Maybe they just exude a type of confidence when speaking that you (or I) don't. Maybe go on YouTube and look up lessons on how to become a successful public speaker and see if they give any tips that you can attempt to incorporate in the way you talk to a group. Don't go out of your way to impress. It's obviously something really small, and maybe it's just the way we are and there's nothing we can do about it. Like I've said many times and mean quite seriously, I don't understand HOW most people think. I wish I did; it would make a lot of situations in life much easier and workable People just don't click with us...and I don't know why.
I hope you took these suggestions in the light they were given. I understand the way you're feeling; I've been there, and I know I'd feel hurt for a long time too. I was just thinking that since you're brave enough to put yourself on the line, maybe there's a way you can get better at it over time and be more respected among your peer groups. Let me know if anything works. I'm curious if I could get better at it too.