Earlier quoted context omitted.
It isnt merely ph adjustment... You want some amount of minerals in water for your health, plants, and taste. Changing the PH isnt the concern in most cases, its just part of the result.
All those filters are specifically made for PH adjustment (you are welcome to look at specs). There are bunch of different formulations depends on how much PH adjustment is needed. RO makes water more acidic. if water was somewhat acidic to start with, it can get more acidic or become corrosive.
The spec doesn't tell you intent it tells you the resulting product performance.
Ph change is one part of the result, not the goal. The goal is water purification.