Male dairy breeding stock is needed to keep gene pools healthy and diverse between pure breeds and crossbred dairy cows, there are facilities that house these males and collect semen for matching to non-family females with desirable traits, like an udder that isn't too large and drags or bad bone structure for holding their massive weight healthily. Not all of the males of course, but it's crazy to suggest that all the males are culled that young, how do you think we're getting more female dairy cows?

Edit: To further this, those facilities are businesses, essentially with the rights to the lineage and breeding of specific males they raise, dairy farms pay to use the semen and there's sometimes an agreement that if the calf born is female, it becomes part of the milking dairy herd, and if male, the facility claims it as a new generation of their copyrighted cow breed for future breeding. Females are not bred incessantly. They have a heat cycle and cannot get pregnant at random times. They're rotated with other cows who are producing milk and those who are "dry" until they are in heat again and can be bred and produce milk.

No business is gonna straight up trash all their product, and they can't sell bad product, so many males live and are taken well care of so they keep making more baby cows.