I ask myself, what is going on here?
Did anyone in 25 years disciple them, at any point, ever, about the reasons why we believe in Christ? It sounds like no one did.
Could these apostasies and semi-apostasies be the fruit of mental laziness? In other words, they never exerted effort to seek out and find writers and thinkers like:
Corrie ten Boom,
J. Gresham Machen,
or Francis Schaeffer?
There is apologetics all over the Internet. If you Googler "Christian evidences", the selections spill all over you.
Do the apostates sincerely believe, in 2,000 years of Christianity, that literally no one has wrestled with, and answered, hard questions? It sounds insincere when they say this, considering how obviously untrue it is. It's a little like saying no one has ever seriously wrestled with the meaning of life.
In a few cases I have read, it seemed like someone was choosing a friend over Scripture. Like, they had a homosexual friend, so they decided the Bible doesn't say that homosexuality is sinful, or that it *does* say that and therefore isn't true. But that isn't valid thinking. The question of, "Is Christianity true?" isn't answered by whether my friend likes it.
My gut instinct is to think that
(a) there are some big ministries who do little or nothing to teach the fundamentals of the faith.
(b) Morality + music with a little Jesus thrown in isn't the Gospel, but there are churches where that's what's happening.
(c) We've been letting baby Christians, or false converts, get into positions of public worship & preaching.