Not the exact wording but the general premise behind it is a fair counter point in any disagreement. When someone is attempting to gain a higher moral authority, bringing up any hypocrisy is a reasonable thing to do. If pointing out hypocrisy is then dismissed, it is reasonable to assume the other person is not arguing in good faith and therefore should no be taken seriously.
But if Hitler said, “it’s not right to just go around killing people at random” it wouldn’t be false because he’s Hitler.
If you don’t trust someone for whatever reason (hypocrisy or what), then the best you can do logically is look more closely at their argument for flaws. Logic doesn’t care about morals or hypocrisy and it’s just not that easy to prove or disprove things. Hypocrites can be right and honest people doing their best to present a good faith argument can be wrong.