Why do these so-called "perfect Christians" insist on trying people's patience?

I'm saved too, but these supposedly Christians keep aggravating me and others by trying to educate me and other people the scriptures what they want to teach on, but leave other valuable info from the Bible out. Then all they do is come up with the real, "well, nobody's perfect you know," as an excuse over asnd over again to justify there pride and self righteousness.