Yes, we do. However, we then must be ready for THEM to "point out" when YOU have strayed, be it ever so small a deviation.
It could turn REALLY ugly in a nanosecond.
It could be ameliorated by a joke of some kind: "Missed Sunday Mass? I hope those Packers made it worthwhile for you. No? Well, there IS always the confessional."
If one is a non-Catholic Christian then one ONLY needs to say "Sorry, Lord" and it's forgiven, even if one sins 100 times a day. PIECE OF CAKE.
Sin isn't a problem with that solution...no confession, no penance, no intention of not repeating. EASY PEASY.
Oh I agree...wisdom is certainly needed. But there are really two issues. Criticizing a brother because we don't think they're doing something right that we don't do perfectly is certainly hypocrisy. But pointing out major doctrinal error is quite another thing. In this case, if one believes that scripture trumps tradition, it's clear that many Christians have fallen into major doctrinal error. Pointing this out with sound biblical references isn't a matter of hypocrisy or nitpicking, but is more akin to teaching others the truth of scripture.