The easy way of viewing what Apple and other companies have done to promote charitable causes is to be cynical. Most companies are not so cold as to be completely involved in charitable causes for PR and image. At the same time, it is not ethically wrong to let others know that you do promote or support a certain charitable cause. In all likelihood, it's a two way street. Companies benefit from the PR, and also, charitable organizations receive greater publicity and more donations. So I think some people unduly think of companies as being "evil," which is unfair. Companies are built by the people.
As an example, Target has donated a certain amount of its profits to charities even before they started making a fuss about it. Now, they let people know that. Personally, I think it's more virtuous to not make a fuss about it. And if it's mentioned, then it should be done so in the proper way. But it doesn't hurt that they do. In the end, the good they're doing is of more benefit than the fact they publicize it. In this case, the enormous suffering and need of the people in South Asia is worth mentioning without second thought.