Welcome back.
I think we've discussed this in the MOM forum, so you may want to do a search there for more answers.
My answer: I can understand why churches would want their leaders to be members. At the same time, the Bible never discussed any membership criteria or anything even remotely close to what we have today, so it's not really a matter of right or wrong, but a matter of what works for the church. Back in the day, membership meant commitment. These days, not so much.
If I were a pastor, I would want my MOM to be a member of the church.