Because they're deranged control freaks who need to convert a single character that is semantically a tab into multiple characters that are an opinionated representation of a tab.
Devs: We need to separate concerns and split the view from the model.
Also devs: Someone might view the code differently!!1!
Devs: We need to separate concerns and split the view from the model.
Also devs: Someone might view the code differently!!1!