We need to realize that there's not a "black and white" distinction between blue and ultraviolet light. (or between other light colors for that matter.)
If you're talking about chemical effects of light of a specific wavelength, there's a bit of a sliding scale. 1 watt of red light has the least amount of chemical effects. Green light has a little more effect. Blue is more, UV is more, X-rays are even more. Even within a particular "color," there is a range of "damage levels." Deep ultraviolet is more chemically active than near UV.
Think of it like a video game. Certain weapons have a "1" damage level. Some have a "100" damage level. The 1 damage level weapon will eventually kill you.
White LEDs have a strong peak in the blue region. It's a valid concern whether this has a long term bad effect on the human eye. Light, especially UV, seems to be correlated to cataracts and other long term "age related" eye problems. Even a small percentage increase in eye problems will mean a lot more cases of serious eye problems. Thousands of people could lose their vision prematurely years in the future.
Suppose that 30 years in the future, we find out that converting all our indoor lighting to LED's caused the cataract rate in the US to increase 10%. That's 40,000 cataract cases per year.
I'm not really all that concerned, but blue light hazard is a valid concern. I'm concerned that the risks will not be considered in the government's frenzy to conserve energy at all costs by converting everything to LEDs.