I agree with you, not only because he did raise his arms slightly, from a "protect the jewels" position to a "blocking" position, but because he took a step towards the defender just before the collision occurred. It's a small step, but sometimes that small step is enough to cause a major wreck.

I don't know what the NCAA rule is about blindside screens like this, but I believe under FED this would be a foul because of the way the defender and the screener were facing prior to the collision? I don't have my books here so I can't cite anything, but recall "instruction" from a supervisor on this.