I absolutely agree, there's no logical reason to disable achievements by using mods,
Come on it is easy to come up with at least one.
They want you to play the game as-is to earn them.
It's their challenge to us.
Good thing for me... I have no interest in them.
But your mileage may vary.
But to me it is very easy to understand why they did it.
I'm also ok if they backed off it.
