[NetMonkey]

My take is that the two are different simple because Apple matters and Facebook does not :)

If you have a product or service and want an additional presence on iOS it is to provide a better service to your customers and thereby increasing your value to them.

When Apple makes that hard/impossible they are decreasing your value to customers which is a problem to a lot of businesses.

The same is obviously not the case for Facebook except for a limited number of cases.