Because, primarily, the person suffering from this disorder is so very sensitive to any signs of rejection. This ravening fear often borders on paranoia and all to often breeches that frontier. In my experience in treatment with those who suffer in this way, the thought or fantasy of rejection is often exquisitely preternatural.
As an experiment in empathy try putting yourself in such shoes and imagine what it must be like, out of your crushing loneliness, to so desperately want a friend, a friend to accept you, sulfurous flaws and all. Yet know that a harrowing flaw your in your personality, a flaw that you consciously or unconsciously know only too well, will command you to behave in a manner that will lead to your dismissal by the very person you so desperately want to accept you.
Yes, rejected once again, and, god forbid, alone again. Alone with a self-hatred and yawning emptiness that, like a cosmic black hole, swallows all in its path. Imagine a self-loathing so barbarously implacable that you cannot see beyond your own hellish abandonment.
Yes. It is the repeated experience of emotional and/or physical abandonment that grinds away in the background of such a stricken person.
It is because of these awful tragedies that I can not brook the prejudicial, and yes, thinly disguised hateful attacks I so often read here on those burdened with the agonizing realities of the mental illnesses of borderline and/or narcissistic personality disorders.
Please, dear readers, silence if not empathy.