It's apparently clear that all the recordings are of pilots and controllers who thought the ship was Egyptian. What's your thesis--that they really knew the ship was American, but they said "Egyptian" on the radio to fool whoever might be listening?
The idea that they wanted to sink the ship to conceal information from us, and then concocted a plan whereby they would lie on the radio and pretend the ship was Egyptian, is just plain ludicrous. The Israelis screwed up and killed some friendlies. We do the same all the time, tragically.