Mental health is a much larger topic than it used to be, (thank goodness for that), but that also means some stigmas come with it. Such as, people have used it as a crutch just to mistreat others.
People with and without mental illnesses have to be cognitive of the way they treat people, period.
You must strive to always be better, be willing to learn from your mistakes. But most importantly be willing to listen when people tell you that you have hurt them. Validate their hurt, and find a way to communicate to each other to fix it.
Unfortunately, not everyone has this mind-set. Nor do the have the drive to make those changes.
No matter what, mental illness diagnosis or not, you must take responsibility for your actions. If you choose not to do so, you aren't allowed to be upset by other people's reactions.
For every action, there is a reaction. Keep that in mind.