It's surprising because the peak of the sun's spectrum is in the green. So the plants ignore the strongest part of the spectrum. That is surprising.
There's nothing surprising here anywhere for people who have actually thought aout this. Please refrain from confusing your ignorance with some kind of general human lack of expectation of this very result.
- Some photosynthetic processes benefit from being executed as often as possible. They thus benefit from chemical processes that absorb in the red, because there are many more photons per wavelength interval in the red than in the green (as a matter of fact, in terms of photons per second per area per solid angle, the sun doe NOT peak in greeen. It peaks in the near-IR). Thus evolution drove towards an optimum of absorption in the red.
Some other photosynthetic processes need as much energy as possible. They thus benefit from absorption in the blue, since the energy per photon is higher in the blue than anywhere else that the atmosphere transmits.
There is thus no reason to expect any biological system to optimize for absorption in the green (other than for non-photosynthetic reasons like attracting insects or such). If the number of photon counts, absorb red; if the energy per photon is more important absorb blue. It would be a rather odd coincidence ever to find something as complex as a biosphere that just so happens to develop a chemistry where the two just so happen to be perfectly balanced in the middle AND is unable to develop more than one chemical pathway to make use of sunlight (photosynthesis has been re-re-re- discovered during evolution many times).