Zeroing a weapon doesn't mean that the peak of the bullet trajectory is at that distance. It just means that the bullet will intersect that point anytime during its flight. In the case of a 50m zero that will be while the bullet is still travelling up, before it hits the peak, and it will at some point further out again hit exactly where you aim.
Also, no one is voting against making sure that sights and the UI-mentioned zeroing distances correlate, but this ticket isn't about that. This ticket is about that a 300m zero would be wrong, and that's what people are voting down.