You are referring to Dana. She has mental health issues, I understand. This does not excuse her from posting the same thing 100s of times and ignoring other peoples point of view. There are some things that you cannot do if you in life depending on your individual flaws. Debating when you are unable to take into account the views of others and to make a relevant response is one of the things that she cannot do.

It's not that you should focus on agitating the hell out of people, but you that doesn't mean you should allow them to do anything. The best thing you can do for someone who is mentally challenged is treat them like any other person. If they are messing up, you're allowed to let them know. If you attack them, insult them, and devalue them as a person, well, that's a bad thing to do to anyone, regardless of disabilities.

Ultimately, it ends up depending on what the disability is. If someone can think and is just being stubborn, even if they lack the ability to gain full understanding, you're allowed to get a little annoyed, just as you would with a non-disabled person. But if a person has a disability that makes them unable to rectify what they are doing wrong or to understand, then you cut them slack. But that is pretty rare.