From the apostates themselves, it seems that it is the association of Christianity with politics -- particularly right wing politics -- in the United States that has caused many youth to turn away.
See, for instance,
this think piece produced several years ago entitled "How to win a culture war and lose a generation". It is the kind of thing that you might expect, but phrased in a way that generated much discussion (509 comments before the comment thread was closed). An excerpt:
So my question for those evangelicals leading the charge in the culture wars is this: Is it worth it?
Is a political “victory” really worth losing millions more young people to cynicism regarding the Church?
Is a political “victory” worth further alienating people who identify as LGBT?
Is a political “victory” worth perpetuating the idea that evangelical Christians are at war with gays and lesbians?
And is a political “victory” worth drowning out that quiet but persistent internal voice that asks—what if we get this wrong?
Too many Christian leaders seem to think the answer to that question is “yes,” and it's costing them.
Because young Christians are ready for peace.
We are ready to lay down our arms.
We are ready to stop waging war and start washing feet.
And if we cannot find that sort of peace within the Church, I fear we will look for it elsewhere.
Dzheremi, the reason for the political war is because of the faith in the risen Lord Jesus includes obeying Ephesians 5:11: "have no fellowship with the unfruitful works of darkness, but rather reprove them."
You need to realize that this is a spiritual war, in which the devil, who from the beginning seeks power, position and homage, (Isaiah 14) and does so by deception, (Revelation 20:10) works to create a world thru his proxy servants in which he perverts what God has ordained, from worship to marriage and more, and thereby glories in the submission of mortals to it rather than to God, and seeks to punish all who will not do so. And in particular this means requiring all to effectively salute the flag of Sodom as it were, or face (at the least) economic sanctions.
And the reason the political war has become a major manifest issue is because of the incessant proactive promotion of immorality by the Left, including and in particular by prohomosexual activists, and intolerance of any that opposes them, despite the clear and documented severe deleterious effects of homosexual relations upon individuals and society, and
which are only condemned in Scripture . If another unconditionally sinful practice was likewise so incessantly and insistently promoted, it also would attract attention and censor of those who seek to uphold morality.
Indeed Christians should be washing the feet of sinners, including homosexuals, and indeed it is evangelicals who are among the
most (or the most) engaged in worldwide humanitarian work out of personal giving.
However, as in the case of
Christian abolitionism , faith is not to be restricted to showing mercy, but to follow their Lord who stated concerning the world "me it hateth, because I testify of it, that the works thereof are evil," (John 7:7) including by stating that fornications (plural), among other sins, defiles a person, (Mark 7:21-23) and specifying that marriage was btwn male and female. (Matthew 19:4-6)
Certainly a believer is to examine his own heart first to see if what he condemns in others in something that he is in some way guilty of himself, and repent of it, but the believer is not be ashamed of Christ and His doctrine "in this adulterous and sinful generation" (Mark 8:38), and is to reprove evil, from calling souls to repent of their idolatry and believe in the Lord Jesus (Acts 14:15; Acts 17:16,17) to injustice against them (Acts 16:37) and to reason of righteousness, temperance, and judgment to some, (Acts 24:25) and thus your counsel to "stop waging war and start washing feet" is actually a denial of faith.
To believe and follow the risen Lord is to do both, as He did. And while plenty of government agencies will "wash the feet" of people at tax payers expense (including by paying for treatment due to the consequences of disobedience to God), very few will warn the wicked of his way, (Ezekiel 33:8) and call them to the risen Lord Jesus who saves us sinners on His expense and credit, not that of their own or their church.
And of some have compassion, making a difference: And others save with fear, pulling them out of the fire; hating even the garment spotted by the flesh. (Jude 22-23)