The glutes extend as well as abduct and externally rotate the femur and therefore stabilize the knee as well as the hip itself. They are also the strongest most explosive muscle in the body so why wouldn't you train them.
Most ACL injuries occur when the the femur internally rotates and adducts, like when you see an athlete land after a jump and the knees go inward towards eachother (anyone see a correlation here???). This is about what it looks like. I see this happen when athletes jump and land, when they change direction and decelerate and obviously when they post up against another player.
Notice the knee, this is where most ACL injuries happen. Not good. See how the hip could pull the femur into correct position to avoid this.
Just to complete this moment of randomness lets go over the difference between girls and guys when it come to the knee.
Knee issues are a huge problem for girls. For one, girls are typically more valgus than guys which puts them at an increased risk for knee issues since their knees are already closer to that dreaded internally rotated and adducted position where the injury most often occurs. But girls are also typically more quad dominant and don't have as much hamstring strength as males putting them at an even higher risk. And not to dig on girls, but to make sure you know that girls and guys cannot be trained the same, but girls typically have more flexibility in the hamstring, sometimes too much in fact and that leads to an increase risk of ACL injury as well.