Q 287

From description of Giants
Rock Throwing (Ex)
Adult giants are accomplished rock throwers and receive a +1 racial bonus on attack rolls when throwing rocks. A giant of at least Large size can hurl rocks weighing 40 to 50 pounds each (Small objects) up to five range increments. The size of the range increment varies with the giant’s variety. A Huge giant can hurl rocks of 60 to 80 pounds (Medium objects).

Rock Catching (Ex)
A giant of at least Large size can catch Small, Medium, or Large rocks (or projectiles of similar shape).
And yet another large giants, such as ogres, trolls, and ettins, doesn't have any of those.
What's up?

(Note: aforementioned SA/SQ not limited to SRD Giants, nor required actual word "Giant" in the name, because there are such examples as Fensir (FF), Firbolg (MM2), and Geriviar (MM3))