Not completely, but somewhat, yes. Gandhi is a terrible example of how to be a husband, but he nevertheless managed to teach nonviolent protest and help liberate a country. MLK also did some philandering, but it doesn't detract from what he did for civil rights. It's easy to be dismissive of a cardboard priest, but if you had an actual human in mind, it would become less black and white.

If you need your spiritual, religious, philosophical leader to be pure as the driven snow, you're going to get some pretty inhuman advice from your leader. Most of us have faults and things we struggle with. If someone doesn't, how do they relate, how do they help?

re: Catholic priest vs. others and credibility, this SMBC comic is appropriate:

http://www.smbc-comics.com/comics/20110503.gif

In other words, it's one thing when someone is claiming to speak on behalf of a deity; it's another otherwise. To be hypocritical in such a context reflects much more harshly on the priest than it does on, say, the civil rights activist.