illegal contact during Free Throw?

[ysong]

According to NBA rule 12-B-I-a: "A player shall not hold, push, charge into, impede the progress of an oppo-nent by extending a hand, forearm, leg or knee or by bending the body into a position that is not normal. Contact that results in the rerouting of an opponent is a foul which must be called immediately."

But during Free throws, almost ALL defenders on the free throw lane spaces extend their arms to lock opponents out. they keep their arms on the opponents even after the ball is released.

I don't think those pushing or hand-checkings fit any of the "exceptions" of rule 12-B-I-a. But what do I miss here? Are those contacts during free throw really illegal?

Thanks.