Pylon inbounds, pylon out of bounds ... here's why a ball touching the pylon (in possession of a player, mind you) is a touchdown.
Any part of the ball breaking the plane of the goal line is all you need. I believe the thinking is, if the ball hits the pylon, some portion of that ball crossed the plane inbounds. Boom, touchdown. Similarly, Bundrage let go of the ball before it touched the pylon. Since it touched, some part of the ball crossed the plane inbounds. Reverse boom, touchback.
Now, as a scientific observer of all things geometrical, I suppose one could make the argument that merely touching the pylon wouldn't necessarily mean the ball broke the plane inbounds (say a gentle caress of the very outside of the pylon without making the pylon move) - but I doubt officials are given that latitude. The ball hits the pylon with enough force to move it, some millimeters of the pigskin must have crossed over the goal line inbounds.
That's what I think, anyway. Now, you want to discuss why replay officials are so darn anxious to do something and overturn calls without absolutely indisputable evidence, I'm there for you. Replay was designed to fix obvious blown calls on the field, not give the replay official the power to make a judgement call on something reasonable people could see either way. I thought the Richardson pass was probably rightly overturned ... Bundrage I wasn't absolutely positive the ball came out before his hand touched out of bounds. I'm biased, I admit, but I don't think there was indisputable evidence to change that call.