Is complete ostracism or social rejection a way of helping someone you claim to care about who suffers with BPD?

I ask because my in-laws are convinced that I have Borderline PD, although I and my therapist do not agree. I do occasionally exhibit symptoms of it, but typically not extreme. I won't ramble on justifying that, just suffice it to say the only people who see me as BPD are my in-laws (and they are all diagnosed with personality disorders of their own, ironically).

So they have decided to turn their backs on me completely, saying "it's for my own good" or something. They keep telling my DH to "protect himself from me, because I'm so manipulative and deceitful." The bad part is that if I did become manipulative it was because it was the only way to survive their games. When I was admittedly deceitful, it was because they behave exactly the ways they projected on me. And I am probably too honest and open with my husband, really. Poor guy.

Anyway, this new "we're not talking to you because you're BPD and this will help you" thing just doesn't make sense to me. I think they're doing it because I stand up to them, call them out on their bs, and now draw healthy boundaries around myself and my husband (although I didn't always stand up for myself, and when I finally did, the attacks began.)

Anyway, is there any therapy that would say to abandon a bpd person you care about? Or is this just an excuse to get away from a person who sees right thru their facades?