But it's actually NOT dark, it's fully illuminated, just facing away from us. While normally this would be a nitpick (it's far side, not dark side!), it actually matters a lot for an infrared telescope.
No matter what they meant, the point is that the idea of putting an infrared telescope anywhere that's not permanently dark and cold is a nonstarter. So it would only make sense to build one on the far side of the moon if it were actually dark.
Yes, but it has its own sunshade, with all the complexity and SPOFs it entails. The point is that at L2 it only needs a relatively small sunshield to block the three way too bright things in the sky, without having to move a lot to keep them shielded. On the lunar far side, it would have to block one whole hemisphere of the sky (ie. the lunar surface) PLUS the sun, which moves in the sky, PLUS insulate the structure from conducting heat from the surface. Oh, and radio doesn't work too well through 3000 km of rock so you'd need a relay satellite system just to communicate with Earth. And you'd need a non-solar source of power for the 14-day lunar night.
But building an infrared telescope in one of the permanently shaded polar craters? That just might make sense at some point, but likely not we have robust crewed infrastructure in place. The polar areas are very attractive from a crewed mission perspective as well, because we now know there are sizeable amounts of water ice there and at the same time on the crater rims you can get continuous sunlight for solar panels.
You seriously did not understand that the post was about building a lot more of the same instrument. That it was not about where to put them. You really didn’t understand that?
