My coach did this. It was because he didn't want anyone he didn't recruit personally and didn't want to feel obligated to take/keep anyone just because they ran a certain time. He also got rid of vet/returning athlete standards at a certain point so he could arbitrarily kick people off the team who he didn't like regardless of how fast they were. Basically it was whether he liked you or not... and yes he did reject/cut some athletes who were actually scorer potential. I could understand kicking someone off the team or not recruiting them even if fast if they had major personality issues (eg. bullying or other antisocial behaviour towards teammates, criminal activities/other serious misconduct, being uncoachable) but that wasn't who he was cutting.
Anyways... he later got fired for being a creep amongst other things.