A huge reason for the incline in counterfeit theology is inadequate teaching of who Christ is. On the left, there is loose theology of who Christ is and on the right there is legalistic replacement of the atonement.
Imagine a house. It's blinds are drawn, the lights are out. The doors are locked, no sound escapes it. Inside that house, there's a war. On one side, there is pure intent. On the other, there is deceptive intent.