Word violation doesn't make sense?

The word "frightening" caused the generator not to show me images. Why is this word banned? What if I want to make imposing, frightening images? The context was "Floating imposing gigantic geometric pattern in natural woodland wetland creek forest. Heavy contrast. Perfect symmetry. Contrasting. Lights and darks. Heavy. Large. Frightening."

I do not feel this should be considered a violation, but perhaps I am wrong, and I understand if the safeguards need to be more stringent than perhaps some would like.