Why don't we just tell the truth here? People are leaving Christianity or rejecting it straight away because teachings on homosexuality and all things LGBT, abortion and euthanasia, and in some instances (especially my church) female ordination, etc won't change no matter how hard they kick, scream, cry, and shout science and sexist bigot etc.
I will agree that right wing Protestant Christianity in the US leaves a lot to be desired. Their denial of climate change, support for blow hard, insensitive, foul mouthed adulterers like Trump, lack of compassion for immigrants, lack of compassion for the poor and supporting policies that keep the poor down and the rich up, is troubling.
But the former and not the latter is really why people have issues with Christianity. Not too many people are too ignorant to believe otherwise.