The USCCB voted 183 to 6 NOT to obey this clear definitive demand from Rome. (So what makes the American Catholic church any less schismatic than the SSPX?)
What a stupid and evil thing to say. Apart from the fact that tu quoque is no defense, it's literally diabolical to seek to advance one's case by adverting to the sinfulness of one's opponent. Your foul and satanic subtext is that sinful men have no business proclaiming the truth. This is precisely how the slavery of sin takes hold: the weak and foolish are tempted to despair at the thought of their personal sinfulness and how far short it falls of the truth of God they're charged to uphold.