because you're right that injuries happen to everyone. But if players 7 through end of bench shouldn't be playing for a D1 school, then those injuries are even more devastating.
It's actually similar to our football team - everyone deals with injuries, but we got a lot and unlike an Ohio St (who could replace two first round drafted NFL WR with a slate of 5 stars WRs) we don't have the same sort of depth behind our guys.