This reminds me of a thought I've had when it comes to what I view as the total failure of the church to maintain strength in the 20th century. I am not here describing the decline as good or bad, only speaking in objective terms that it happened. The church bowed to society again and again despite specific prescriptions against that. To paraphrase, "society is base, wicked, and wrong"
Christians are to be separate from society in their behavior while living within it and showing to others their lives in service of Christ. Within Christianity it is maximally wrong to reevaluate doctrine because of what society thinks and yet it is clear that every "progressive" denomination has established their position on homosexuality because of society. I don't have a religiously-motivated censure here, but I do criticize for inconsistency.
Progressive denominations have pastors who preach these things. I've heard of churches teaching intersectionality, and while I've never been in such circumstances nor do I foresee myself there I'd like to think that if I found myself in one I would speak out against it. This is because the types of churches that are so progressive as to invite speakers or have their leadership talk about these subjects are most likely already heavily involved in outreach efforts for the poor and the homeless and the LGBT/GSM community, and browbeating some of the kindest and most charitable people around with even more original sin doesn't sit right with me.
But back to the point, this is the leadership teaching these things. What happens in Christianity when your own pastor is teaching you incorrect doctrine? I have this same question on the thousand+ years of Catholic congregations who were illiterate and may have been taught things out of accordance with scripture because they couldn't learn the truth. I'm not saying the specific subjects I've elaborated upon are completely theologically settled, but you can understand the broader concept I'm pointing at. What's the answer there, when someone wants to be a good person and the person in charge of teaching them Christianity is wrong about it? What happens when that's never corrected? What would a just God do?
What happens in Christianity when your own pastor is teaching you incorrect doctrine?
Start a new denomination, just like every other person who felt their pastors were teaching incorrect doctrine. Or join one of the thousands of extant options.
Your position feels rooted in the sort of modern Protestantism where every denomination of Christianity is all basically Christian, everyone who accepts Christ is going to Heaven, and whatever minor doctrinal disagreements everyone has can just sort of smooth out. Except for Jehovah's Witnesses, who believe wrong. And Mormons, who also believe wrong. And maybe Seventh Day Adventists, who believe wrong-ish. And maybe Catholics, who believe wrong but might be grandfathered in anyway, depending on who you ask. My own religious experience was a bit different. I've long ago lost count of the number of times I heard this story:
My mind at times was greatly excited, the cry and tumult were so great and incessant. The Presbyterians were most decided against the Baptists and Methodists, and used all the powers of both reason and sophistry to prove their errors, or, at least, to make the people think they were in error. On the other hand, the Baptists and Methodists in their turn were equally zealous in endeavoring to establish their own tenets and disprove all others.
In the midst of this war of words and tumult of opinions, I often said to myself: What is to be done? Who of all these parties are right; or, are they all wrong together? If any one of them be aright, which is it, and how shall I know it?
The history of Christianity is a history of schisms. Even the schisms have schisms. Take a look at how many denominations exist within the latter-day saint movement alone. Most of them I've barely even heard of, and I lived and breathed this stuff for years. Christianity's been changing all the time, with different branches rising up to meet different real or perceived needs, each one claiming to reform or restore something critical that's been lost.
Heck, the tendency to schism extends far beyond Christianity itself. Ask the Baha'i, who could be described with startling accuracy as "Islamic-descended Mormons." That's a parallel for another time. The point is that "Everyone is practicing Christianity wrong" is an experience as old as Christianity itself. Given that Christ himself came along and called out the Pharisees and Sadducees for practicing a corrupted version of their own faith, I would say older, even. As old as religion itself.
It can be interpreted in a faithful way or a cynical one. I choose the cynical take these days, but I wore the other hat long enough to know that it's possible to use widespread flaws in the beliefs of others as motivation to stay on an orthodox, faithful path.