Safeties

The Violet Flashlight's belt wasn't made by her. Her own soul powers the thing, and the effects are as strong as she is, but she's using a stolen prototype weapon made by an artificer for testing weapons for his hired soldiers. The inability to affect anything green has a very simple root cause:

The artificer wanted an easy defense against and an easy way to conrain his test subjects. The device refuses to work on anything green... which is a simple paint job away from making cell walls the victim can't blast through, a simple dye job on some cloth for safety gear for the tester. The green bullets amd guns for termination tools were a mild annoyance, but easy enough.

He didn't realize until too late that telekinesis applied to the gray boulders in the test area, rather than the tester or the walls themselves, made for a fine workaround.