If you work at a gas station and in the middle of the night a man walks up covered in black from head to toe, not letting you see who he is, or any identifying features would you also think he might be of good intent? If he was truly not of ill intent he would have uncovered his face and let you identify him wouldn't he?
I respectfully disagree. Perhaps these entities don't possess enough strength manifest fully, or maybe their "facelessness" really is their complete form. Or perhaps, operating on the theory that they are from another "plane of existence", a part of them is "stuck" on the plane from which they originate, thus inhibiting them from attaining full manifestation and the ability to communicate. So many possibilites!