It seems perfectly normal to you because that is what we are used to our entire lives. But it is wrong. The proper order of the sacraments are baptism, confirmation, then Holy Communion. It is exactly as the article said, it has led to a complete misunderstanding of the sacrament of confirmation, it has denied children graces they need growing up.
The sacrament of confirmation has nothing to do with becoming an adult. In most religions? I think we can say the only examples that matter are the Eastern Orthodox, Eastern Catholic, and Roman Catholic Churches. Take out the last 100 years of the Roman Catholic Church and you “perfectly normal” idea falls apart pretty quickly.
I will say that the 1983 code of canon law tried to fix the problem, specifying the age for confirmation in the West should be the age of reason. Unfortunately it allowed Bishop conferences to override this, and the bureaucratic inertia in many dioceses allowed the wrong approach to continue.
ETA: I will add that I have always question if the bishops of the US are actually following canon law with this regard. It allows the bishops conference to set an age, not individual bishops. The USCCB, from my understanding, decided to leave it up to individual bishops, which does not seem to be valid. They should either set an age or leave it at the age of reason.