Counter argument against the deflationary theory of truth
Alex denies the correspondence theory of truth in favor of the deflationary theory, and whenever I've heard his reasoning for this it's been this one specific argument. The premise is that whether you say "The sky is blue" or "It's true that the sky is blue", there is no difference in the meaning of the statement. And since you can remove the "it's true" part without changing the meaning, he concludes that truth must not be a very meaningful concept.
The thing is, while those two sentences do in fact mean the same thing, that's because the concept of truth was already implicitly involved in the statement "The sky is blue". Putting "it's true" at the beginning merely makes that more explicit in the wording, but doesn't change the underlying semantics at all and is ultimately redundant. The word "is" already contained the idea of it being true, and if you thought it was false then you would say "isn't" instead.
Once you take this into account, the conclusion doesn't actually follow. Nothing about these two sentences meaning the same thing indicates that the concept of truth is any less real, meaningful, or objective.