Removing the shirt in celebration of a goal is a YC offence. Removing the shirt whilst leaving the FOP with permission is not as far as I am aware.
Very harsh YC in this vid, but the question to vote on was referencing goal celbrations, and yes, I do think cards should be used in certain circumstances.
As I understand it, the shirt removal offence was introduced to prevent play being held up unneccessarily, (see Diego Forlan at OT), it accompanied rules about commercial messages on undershirts etc etc, so it is more about the commercial sponsorship rights than an offence against an opponent or the game itself.
As far as goal celebs are concerned, I do feel that higher up in the game, there is a safety factor to consider, and I believe the cards for 'over-celebrating' were introduced with this in mind. Players running to the opposition fans to celebrate a goal for example, or running up to their own fans and causing a surge forwards. Dangerous for those involved, player and spectator.