The reason to point out hypocrisy in politics is to get down to what the person really wants. For example, the pastor who preached against The Gays, and then ends up being convicted of grooming children. He obviously wasn’t going after LGBTQ+ people out of some moral stance, so we look for other explanations. Gaining political power is one possibility.

In general, logical fallacies should be used to pick apart your own argument, not throwing it in other people’s faces.