I'm not great with redstone but I think your issue with understanding this is the fact that the torch is on the side of the block and thus one block too far removed from the power for it to be transfered to the torch, unlike the torch/block/torch arrangement beside it.
The redstone toorch on the bottom should be powering the block that the top redstone torch is on shouldnt it?
Proof that block is getting redstone power:
by c0yote
I tried it with terrible results. I gave my wife my glasses for a second, a creeper showed up and now my wife is pregnant.
Stupid 3D..