It's theater people!!!!! Almost everything in a U2 show is staged...from the positioning of the band to Bono's speeches which are written for him. It's the same calculated, BUT very effective routine EVERY night. That's what makes Bono the ultimate frontman--he can sing and act.
Haven't you ever heard him speak about this song--he tells the SAME story during every interview. "My father was a postal worker who loved the opera. He conducted with knitting needless..."
Don't get me wrong, if the song touches you and makes you emotional then you're experiencing the music on a different level--go with it. That being said, this "teary eyed" (probably sweat) Bono is no different then him playing McPhisto...it's all part of the act.