There needs to be better support for the mentally ill as they are suffering from actual diseases that are horrible to experience but also costly to society if left unchecked.
The mentally ill need the empathy of others and the right resources to get better, but instead are often subjected to stigma along with efforts to undermine access to the care they need.
That said, many mental illnesses are not at all conducive to fostering the qualities that make a person likable or a good friend or partner.
Take a depressed person for example, they can easily make for shit company and be very self centered in their thinking. They may not be able to offer much making for a lopsided relationship.
They might not be "fun" to be around--
they're too negative,
too whiny along with other traits that can be instinctually off-putting. They may start to neglect their self-care.
So it's easy and kind of understandable to be like fuck that guy, especially if you're not a family member and unaware of their situation.
I'm using depression as an example, but there's also all the anxiety and personality disorders, along with fun stuff like addiction, bipolar, schizophrenia, and more.
Since these are diseases affecting a person's cognition, and in turn their actions and behaviors, they might become absolutely soul draining to deal with or in some cases outright abusive.
I can't fault most people for cutting off a mentally ill person who may be in desperate need of help and support but who has become too
t o x i c to be around.
Even therapists often limit the number of borderline personality disorder patients they take on because of how difficult and draining they can be to work with.
Basically, mentally ill people can suck sometimes in large part due to whatever they're inflicted with, but unless you're a professional most people aren't going to know or care and simply judge them at face value.