It actually isn't. The dominant frequency of solar irradiation is dependent on choice of spectral variables and could just as well be said to be in the infrared, when plotted as a function of frequency. So with the same argument, plants would be better off reflecting that. Especially when you consider that absorption happens as transitions between energy levels (i.e. frequencies) in molecules. However, in truth it simply doesn't make sense to talk about point frequencies in a density distribution.

[1] https://www.oceanopticsbook.info/view/light-and-radiometry/l...

The math to compare colors is more simple than that: https://www.w3.org/TR/WCAG20/#relativeluminancedef

Blue is a slightly higher frequency than both red and green but green has a dramatically higher luminosity. Simple arithmetic applied against that less simple luminosity formula allows for contrast comparisons.

We're still talking about the solar power density here though. Ofc blue is a higher frequency than green, noone disputes that. But you can't technically say green is high(er) in the solar power spectrum.

Hah I love these cycles of [dis]information and correction on Reddit/HN:

> Commenter A: [cool fact]

> Reader: Oh! Interesting!

> Commenter B: Actually no

> Reader: Oh...

The energy of (one photon worth) of electromagnetic energy does indeed increase with frequency. So green is more problematic than the same number of red photons. But you're right that if there were few green photons coming in and a ton of red, red might be blocked, and green not.