Some of the scariest people I have ever met are people in helping professions. They're teachers, or therapists, or alt med healers, or whatever. And they have nothing but the best of intentions.
This sounds lovely, but is actually very scary. See, they mean to do good. Often, their entire self concept is built around being a Good Person and their mission in life being Helping People. These are noble goals and all, but when you make them your whole Who You Are, you can become a scary person.
These helpers just cannot wrap their head around the idea that they can mean well all the live long day, but that doesn't mean they are doing well. Some people who are helpers? Their chosen method of helping actively hurts people. And they cannot process this-they are Good People and Help Others, they can't possibly be doing damage! That's the other social skills therapy or whatever, not theirs! They mean well, you see. They are Doing Good. They couldn't possibly be accidentally hurting people!
And they take it as a personal attack. People do not react well to what they perceive as a personal attack, especially against their very core, in this case the idea that they are Good People who are Helping Others. Rather than evaluating if, from the perspective of their victims...uh, clients...they are causing harm, they lash back. They can't wrap their heads around the idea of anything but their intent, as if trying is the same as doing. Their self concept seems to be more important than actually being helpful. It's like it doesn't compute that they could be wrong.
This is really scary. You never know what people are so caught up in this idea, so you don't know how they react if the harsh truth that their chosen therapy hurts people. Unpredictability is scary, as are people who would rather believe I am trying to hurt them because I am an asshole then believe that maybe, just maybe, their intention is not magical.