Because you can't put the oil back in the Earth or bring back 11 dead men as easily as you can take back an iPhone.

They might appear to be logically equivalent[1], but one clearly has hope of gaining empathy from the public and the other does not, especially considering BP was already on the hot seat about their safety record.

[1]I don't think they are - Apple's design decisions are no where in the same league as BP's ongoing record of putting the health of their employees at risk. The only entity benefitting from BP's decision would have been BP, whereas the antenna design supposedly gives better reception when the signal is not being attenuated by the user's grip.