First, byu has very few masters programs and is primarily an undergrad program.
Second the mission of BYU is only to have grad programs "of distinction". In other words, it is hard to get a master's program approved. There are no easy grad degrees like some schools have on meaningless topics.
Third grad programs make the decisions on admissions, not byu.
Fourth grad school is way different from undergrad. The hardest part of my job hands down is advising a grad student who is not performing well. Because there is a much higher level of mentoring and involvement, if the person isn't a good student it is going to be a time sink for me. So faculty scrutinize admissions closely looking for a good fit to their research.
Fifth, we are capped in how many students we can have. If we accept someone not deserving then that means someone more deserving doesn't get in. And each of these applicants has a compelling story, most about how they need the degree to progress and provide for their family. It is excruciating and difficult each year to do grad admissions.
Sixth, byu doesn't tell the faculty who to admit. We had a grad coach wannabe apply. I think I was the only faculty member who knew.
Finally, all of this is for good reasons. It is a good thing that byu is primarily for undergrads. That means more of your kids are able to get in