This is exactly correct. The flavor from the hop oils binds with the glycosides in the wort, essentially "locking" them into the wort. Since they are now chemically bonded to the wort and are no longer in their original form, boiling the wort doesn't burn them off like it normally would. Adding hops before the boil adds massive, smooth and wonderful hop flavor.
Anyone who doesn't believe us obviously has never tried it. Brew a batch and only use fwh and you'll be quite surprised!
Remember, they do impart IBU's. I find that they impart the same amount of IBU'S as if they were added at 60 minutes.