Couple reasons: #1, I assume that because Saint-14 died IN the infinite Forest, that's why we can bring him back. Because it's wonky with time and stuff. I even have a feeling there's gonna be a plot thread where Saint-14 can't leave the infinite forest because he's actually still dead, but being kept alive in the infinite forest through simulation. #2, Cayde literally said in his will he didn't want to come back. Granted that was referring to him being rebooted, but he still said to leave him alone.
Your opinion makes no sense since the cabal are using it to change the outcome of the red war which took place outside the forest as well
That's actually a pretty fair point.
Time Travelling Vex tech. Osiris built the Sundial on Mercury after he learnt of Saint-14’s death, so the machine is obviously piggybacking off the planet sized computing power.