I think the intended meaning is as follows:

Similarly, you can eliminate the [word] 'rational' from almost any sentence [you utter]. [Saying] "It's rational to believe the sky is blue", [saying] "It's true that the sky is blue", and [saying] "The sky is blue", all convey exactly the same information about what color you think the sky is - no more, no less.

As you pointed out, the first sentence is not logically equivalent to the second and third (the second and third are logically equivalent according to Tarski's semantic theory of truth).