Yes—you have to give them credit. They think they are doing the Lord’s work.
Yup; and they are even mentioned in the Bible!
Galatians 4:17-18
Those people are zealous to win you over, but for no good. What they want is to alienate you from us, so that you may have zeal for them. It is fine to be zealous, provided the purpose is good, and to be so always, not just when I am with you.