I think they should generally play the positions the way they’re designed to be played. When uber analytics begins changing the fabric of the game, I become less of a fan (of the control analytics has on things). Yes I’m sounding old. I’m okay with that.
But your post is correct. The rules as they are today, you have to do it.
If someone hit the ball right up the middle 20 feet past 2nd every single time and was batting 1.000, even the most Joe Morgan of traditionalists would yell and scream how you can't let him do that. The shift is no different imo, just on a lesser scale.
Players standing where they stand because they decided in 1880 that was the best way to get guys out isn't imo the fabric of the game or how positions were "designed to be played" but that's me. I'm getting old but am very open to disrupting traditional thinking. Hell, I have mostly liked most of Harbaugh's decisions so that will tell you how I feel about these things, and I'm okay with that.