Yeah! Exactly! Even those are extremely stupid and non-logical. So why bother making them?
Mmmmh... I think you are kind of biased on this one, atleast, regarding to what I've seen over the years.
Achievement hunters, like me, usually hunt them just to have a DEEPER experience of the game, in order to study more the mechanics and design of the game.
Personally, I don't have THAT much money to buy every single game I want, so when I get one, I usually play it to the very end, achievements included (if they are not stupid like some of the ones I mentioned). Plus, trying for achievements, made me more critic on games that at first they seemed masterpieces to me.
I mean, always better than those who play the game for 1 hour and immediately say "OMG BEST GAME EVAH!!1!1!1".