FM needs to be activated! For emergencies. What if the power goes out and internet/phone service access goes with it? Natural disasters happen and having FM radio access to hear emergency and news updates would invaluable. Think beyond your daily activities people!
For this very reason I keep an emergency FM radio at home. It can be powered by hand crank or AA batteries (I stock NiMH rechargeable cells with low self discharge, as well as conventional Alkalines as backup).
I have always found Apple's decision to disable the FM receiver to be perplexing. Most cell phones with FM tuner use the wired headset for an antenna rather than an antenna on the phone itself, so there should be no technical hurdle there. I suspect it has to do with Apple's propensity to delete older tech like floppy drives, optical drives, and ports.