We do see "violet" light, but it activates only our blue-sensitive cones (and not as strongly as does blue light). Sky-blue light also activates our green-sensitive cones very slightly. What we see as sky-blue contains a little bit of green (but only in the way we perceive it).

You know how the sky has different shades of blue? Well, a part of that is determined by differences in the spectrum of light that actually enters our eye. Where the sky is an intense, deep blue, that is mostly the shorter-wavelength stuff. Where it looks a bit less intense (and not just the "washing-out" effect caused by looking through more atmosphere, as the sky overhead can appear different shades of blue at different times of day and on different days), there are some slightly longer "blue" wavelengths involved as well.

This has been known for decades, so I do not quite see what this new discovery is meant to be.

Anyway, I thought there were two effects at work - one scattering (absorption / re-emission at different intensities for different wavelengths) and one refractive.

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The quarrelsome oarsmen were rowing,
The great violinist was bowing;
But how is the sage
To tell, from the page:
Was it pigs or seeds that were sowing?