intentional foul?

[akingsfan]

I was watching a high school girls game a couple of nights ago and saw the following and was wondering whether the call was appropriate or not. It was the last quarter and A1 had stole the ball and was going in for a lay up. B1 was running beside her (both going hard towards the basket). A1 goes up for the layup and B1 jumps with her trying for the block and preventing an easy layup. B1 actually hits some ball (not a clean block but obvious going for ball). The contact and momentum sends A1 to the ground or close to it cause B1 tries to hold A1 up to keep her from hitting the ground. On the play, the ref calls an intentional foul, which observing the game, I thought was a very bad call seeing that she was going for the ball. My thoughts have always been that all hard fouls are not intentional and not meant to injure someone, but most of the time just prevent a shot from being made and the chance for a three point play. Any thoughts on the above scenerio would be appreciated.