On your first thought and looking at the spirit of the OP, if someone gets to a point of not being able to reconcile certain beliefs as being accurate, any standards coming from these beliefs will lack credibility and is a key reason young people are leaving the church.
Then they should leave. Nothing wrong with pruning the tree from time to time. If somebody was only in the church because they were persuaded by an argument, then they shouldn't have been there in the first place.
I'm all for the Biblical idea of church being for the ecclesia and not for the goats.
We Baptists are notorious for over-inflating our numbers. Probably 75% of the people in our churches have no business being there.
Those people who come and act as spectators, never learning, never participating, never being prepared for ministry, never offering anything, are rebuked in scripture and yet, our churches are full of them.
You try to portray people leaving as a bad thing, but you forget that, if the issue is people leaving, then the most important question is, who are those people and why were they there in the first place?
People who were brought by mom and dad as children and then left once they were no longer compelled to be there? Being made to go to church by mom and dad doesn't make one a Christian. It doesn't make one eligible for church membership. That person is still responsible for their selves and if they never got saved, then they shouldn't be there.
People who grew up in a Christian culture and attend church because it's what their family does, what their neighbors do, because they like the songs, the nice little inspirational message, the social aspects? I'm from the Deep South. That's 90% of the Christians down here. They grew up with an affinity for Christian culture, they know the appropriate points in the preaching to holler "Amen", they know all the songs and may even have a Gaither or Hee Haw Gospel Quartet CD in their car, and they play on the church softball team, they don't drink and they don't chew and they don't run with them that do, but they never repented and they never received Christ? Just repeated a canned prayer? Let them leave.
Doesn't mean we don't love them or love them any less or that we pluck them out like tares, but the Bible is pretty clear that the Church is for the Ekklesia, not for the goats.
We'll continue to love the and we'll continue to welcome them when they want to visit and we'll be the first ones to bring supper to their home if something happens, if they're apart from Christ by lack of any kind of salvation testimony or evidence of sanctification, then they're just not eligible.
I know to the non-Christian, that sounds harsh, but it's Jesus' Church and if that's the way He wants it, then it's not our place to change it.