I don't think being direct and honest is a sign of a mental illness. Where in the world are these people getting that from?

Now, if that honesty is very hurtful or socially inappropriate, then yes, it could be a sign of a problem of sorts.... a social ineptitude, let's say, or something else, but not necessarily mental illness. However, I am no psych doc nor do I pretend to be one on TV, lol.

Bottom line is: as long as that honesty is in an effort to be completely open about what is happening in your life, or in someone else's life, then there should be no issue. I appreciate it when my friends are very honest and direct with me, even if it's not what I want to hear, so there's that side of it too.

Hope I didn't misunderstand the question.