[MizunoJoe]

Because he is already rotating hard. If you throw ONLY, yeah the R elbow would straighten. But remember he tried to fire hose hips at Startdown, which really cranked up the rotation, and his L side extension allows that rotation to get even faster. Pure PA4. Then at Release/hands hip height, he starts thinking fire that R arm in sidearm/undermine throwing manner.

IMO, the more of what he did in BS, the RFT, the longer the R elbow would be bent and closer to the R hip.

Remember this is a very fast motion. The R elbow suddenly straighten starting visually right at Rekease/shaft parallel in DS. From thereon it straightens slowly as the DS is very fast. His R arm and R wrist is very very straight in followthru. Note also that his shoulders don't turn/rotate as much in finish like Immelman for example and Tiger circa 2000. So I'd say it's more PA1 for Hogan from shaft parallel, but he's also still rotating due to the earlier hip turn crank.

It's not humanly possible to rotate hard enough from release to impact to prevent the right hand from moving farther and faster than the right shoulder, if he's throwing. He isn't throwing the right forearm, it's getting thrown. The right arm is straightening in the release interval, not because he's throwing, but because the LW is uncocking from rotational force.

Apparently you forgot how fast the motion is when you previously said that Hogan starts thinking at release point!