That is 100% true. Unless you are trying to compare yourself to someone else (leaderboards and stuff), its fine to cheat just to make the game more fun, for example I almost always cheat by turning off natural regeneration.You are taking an intentionally slow and tedious process, one that is slow and tedious to balance the fact that it's infinitely renewable, and you are cutting it down to 1/100 of the time. It is blatant cheating.
Cheating isn't bad, everyone should enjoy games the best way they can, I mean I cheat and turn of enviromine stuff so I can relax and play at my own slower pace. It is what it is though, anything you do to the pack to make anything in it even slightly easier is cheating.
I've cleared like 15 bunkers and haven't found one, I think they are probably too rare from those to be a realistic quest goal. The quest doesn't say anything about finding one anywhere either, so I think it's either not supposed to be a disabled recipe or it's something that was changed after the quest was made and it was never updated.
Edit: And the quest to build the rocket apparently wants a basic rocket with no storage. I added 3 chests to mine because I can't see why I'd want to build one without them, but it didn't complete the quest and I don't know if I can take them off now.
I guess you are playing on old map. Those bunkers were added in 1.2.6, so you may need to make new chunks to find them, I made this quest before when it was still craftable.