1) I believe the touchdown was called back because of the illegal block to the back, not the personal foul. You may say the illegal block call was bogus because it was just a little shove--but technically that's a penalty, either way.
2) I have a lifelong friend who both coached and served as a broadcast color analyst. His thoughts on this: a) referring is very hard in any case; b) in the NFL, it's almost impossible because of the extent of the rulebook...the 'points of emphasis'...and how often both change. In his view, refs aren't partisan--just overwhelmed.
3) On Carroll, he wasn't known as Pete the Cheat for no reason. His sordid tenureat USC is a matter of record--ESPN documented it with a 30 for 30. You may also remember him during one of the Super Bowl runs a couple years ago admitting he told his defensive backs to hold whenever they wanted--"they're not going to call it on every play"...or words very close to that effect. Personallly, I find him a total fraud--but I guess that's just me.