We all commit sins and make mistakes. And by acknowledging that fact, it implies that it is within our capacity to judge either inwardly or outwardly if something is amiss.
And it is our duty to call the wrong things we see despite being imperfect ourselves. For justice and order could only be attained if we guard each other's actions since most of the time, we misjudge our own deeds due to personal bias and survival tendencies. No one should be beyond criticism. And being shut down for whatever reasons including being called out for the mistakes that one had done in the past or in the present is an injustice in itself. The proper way to address criticism is to listen first and reflect, not to look for ways to criticize in return and be defensive right away. Everything has its time.