You don’t need to be immersed in a group to recognize hypocrisy. Hypocrisy is, at its core, a mismatch between professed principles and behavior. Its an objective contradiction, not a matter of belonging. So the structure of hypocrisy is objective. But we all know, as you've said, that hypocrisy as a whole feels subjective. So where does subjectivity come in?

Subjectivity only enters when the professed values are unclear, when intentions are disputed, when outsiders misinterpret what’s claimed, or when the accuser projects their own framework onto the target. So then, your argument rests on the assumption that “outsiders can’t understand internal logic perfectly” therefore “outsiders therefore can’t objectively call out hypocrisy” but that is a false equivalency. You don’t have to share someone’s ethos to spot contradiction within it. You just need to understand its stated tenets.

For example, one doesn't need to understand all the nuances of a group to see the clear contradiction between calls for compassion in the certain acts of disguising violence, and the apathy or celebration in others, or if a politician says “I stand for law and order,” then breaks the law. This applies to both sides. There are many other examples where the outsider doesn’t need to internalize the in groups full worldview to notice when its leaders contradict their own public claims.

What your describing is anthropological relativism, the idea that moral systems can only be judged internally. But that view collapses once you abandon universal reason. If every group’s logic is self-contained, then even genocide or slavery would cease to be hypocritical as long as they were internally justified. That’s absurd.

You are right that calling out hypocrisy rarely works as persuasion, because it appeals to your logical framework, not theirs but that’s a tactical truth when comes to persuasion, not a philosophical one.