One of the main problems around people with personality disorders (particularly cluster B), psychotic disorders, OSDD/DID/other CDDs or other stigmatised mental conditions is, well... Everything we do gets put back onto our disorder. Every fault, every misstep, every mistake is used as proof to say that the stigma of us all being horrible people is right.
We can say "not everyone with x disorder harms people, and in fact we're more likely to BE harmed and abused than we are to hurt others" as much as we like--and of course, that's a true statement. But the moment someone with a stigmatised mental illness does something wrong, it's "of course you'd do xyz, you're a narcissist" or "checks out with the psychosis".
Someone with ASPD could cut someone off for any valid reason, but anyone else could spin it into "yeah, that's sociopaths for you". Someone with psychosis could wrongfully accuse someone of something and without being given a chance to apologise, suddenly it's "this is why we don't trust delusional people like you" and you're discredited from here on out. Someone with DID could genuinely forget that their alter had an argument with someone and be trying to sort it out, but no one wants to hear that something was forgotten in the amnesia, so and all they get is "see, people with DID just blame everything on their alters".
People with stigmatised disorders are just like anyone else. They're not evil or uniquely capable of harm, but that also means they're not incapable of making mistakes. Everyone is entitled to their own limits but I think people need to be more aware that disabled people can make genuine mistakes and one slip up or argument doesn't mean that pwNPD is secretly manipulating you. Sometimes people are manipulative and you need to be able to tell the difference--just like neurotypicals, disabled people can be abusive. But blaming mistakes or even genuine malice on someone's disorder does nothing but harm a marginalised group of people. If you wouldn't say "of course you would, you're neurotypical" to someone abusing someone else or if that wouldn't make sense to you, why would you do it to disabled people?