The better you are at lying the better you are at clearly presenting any thought, including thoughts that are true, or neither true nor false.

This is false for the case of clearly presenting deductive arguments, which are a non-zero portion of "thoughts that are true". (They are also probably a lot more significant, on average, than the average thought that is true.)

Your ability ... to understand ideas doesn't give two beans whether the ideas are true or not.

This is a thread full of evidence that the quoted phrase is either not specific enough, or incorrect for a subset of people.