Because they are electrically neutral, there is no direct interaction between photons, which is good, because it allows us to see each other even when there is light coming from all directions. At low energies, that's the end of the story as the interactions via intermediate particles are incredibly unlikely.
However, think about how an electron and a positron can annihilate into two photons. As the electromagnetic interaction is symmetric under time reversal, the reverse reaction should be possible, as long as sufficient energy is available. So an extremely energetic photon can combine with a photon from the background starlight and turn into an electron-positron pair, essentially being absorbed.
However, think about how an electron and a positron can annihilate into two photons. As the electromagnetic interaction is symmetric under time reversal, the reverse reaction should be possible, as long as sufficient energy is available. So an extremely energetic photon can combine with a photon from the background starlight and turn into an electron-positron pair, essentially being absorbed.