We've overflown the Mediterranean many times.
Why is it heroic when Israel does it?
Because they take on proportionally bigger opponents than we do.
Don't know how "heroic" it might have been. But it was a message. The same message that SAC used to send with it's non-stop around the world flights. Only both more and less so. By demonstating that they had the capabilty to conduct a *conventionaL* strike at the same distance as Iran is from them, they've made such an attack much more credible. Without the ability to condict a conventional strick that from from their own airfields, the Israelis woudl be stuck with the Samson option. Nukes, on missiles. The lack of necessity for using nukes, makes any threats more credible.
Hopefully, like with SAC, the message will be received and their will be no war, but with Amanutjob, it's hard to say if any deterence, short of introducing him to his 72 virgins and the 13th Iman would do the job.