1. Obviously some achievements are easy, why are you complaining about ones which actually require some time/effort to complete though?There are literally achievements for pressing start in games. Prey itself has achievements simply for progressing through the story. If you honestly believe that all trophies or achievements are REAL achievements then you have a low bar for success. Killing all humans in Prey is not an 'achievement'. It is not difficult to achieve. It is not something to brag about. It's just a way they force shitty replayability into their game so you don't trade it after you beat it in your first weekend. And I don't like that.
2. You have no idea how difficult it is to kill all the humans in Prey. They might be all over the place and hidden in hard to reach areas. Some might be ridiculously powerful for whatever reason.
3. They're not forcing any replayability, you can literally just ignore achievements. They're included for those who want to replay the game and incentivise unique ways of doing so.
This is one of the most petty and nitpicky complaints I've ever seen about a game...