Simply because there is examples of things that we thought to be safe but were in-fact harmful does not award you the right to make bold claims without the proper evidence. That would be a very slippery slope. If you believe something to be harmful, go and prove it.

Because we were wrong in the past about some things, I'm going to make the claim without evidence that visible light kills. Everyone who has ever died of cancer was exposed to visible light for very long periods of time. Don't expose yourself!