Wrong. It is rejected l’maaseh, not conceptually. In fact, to some degree we practice it l’maaseh when we fast on a taanis, and even until recently, probably even today, there are people who fast more than just on taanis tzibur.
Something isn’t rejected from Yiddishkeit simply because you don’t practice it.
The reason we don’t practice it is because yotzo schoro b’hefseido, since it will hinder our davening, learning, and other avodah, not because we reject the idea.