That is the typical "bottoms on pews = successful church" reasoning that I hear all the time. IMO, the main purpose of a church is to serve as a meeting place for people to worship God. A church in and of itself is not going to save people. Only God saves people. Going into a church and sitting on a pew and listening to a sermon is not going to save anyone. I've seen many people start attending a church because their kids want to go. Those parents sat there week after week and never really became believers (I carpool with one). Sitting in the church did not result in some magical transformation or osmosis. Church is ultimately a place where the saved sinners can go and worship with other saved sinners. If there are people going to a church who do not like the form of worship at that church (don't like the music, don't like the preaching style, disagree with doctrine, etc), they can go elsewhere; as there are only a gazillion churches from which to choose.
Pro LGBT supporters who go to churches that are not already pro-LGBT go there in an attempt to undermine the beliefs and doctrines of those who are not pro-LGBT. It is time that Bible-believing churches accept the fact that those people are 5th columnists who want to betray the church to the enemy.
So, if membership declines because people who could not accept the doctrine chose to leave, then the church probably should die because there is not enough living tissue to support the tree after all the rot is cut away. I would choose a dead church over the first United LGBT Church of the Rainbow Banner any day. And I am getting tired of hearing namby-pamby cliches like "hate the sin and love the sinner" while the LGBT'ers take over everything. They are locusts who consume everything in their path. Church should be a sanctuary from the LGBT crowd, not a haven for them.
Your opinion does not match up to the opinion of the teachings of the New Testament.
The church is not a place for saints to gather and hear good things about themselves and bad things about unbelievers. The local body of Christ is compelled to reach out and save their community, to send out those who will invite those outside of the body of believers to come in and hear the good news of Christ.
Jesus himself showed us the method of reaching out to others:
When Jesus traveled to Jerusalem, he was met at one point by ten lepers who called out to him from a distance.
"When he saw them, he said, “Go, show yourselves to the priests.” And as they went, they were cleansed. One of them, when he saw he was healed, came back, praising God in a loud voice. He threw himself at Jesus’ feet and thanked him—and he was a Samaritan. Jesus asked, “Were not all ten cleansed? Where are the other nine? Has no one returned to give praise to God except this foreigner?” Then he said to him, “Rise and go; your faith has made you well.”
He gave his attention to ten and only one came back to thank him. And that one was a Samaritan, one who was reviled among the Jews.
Can we do no less? Invite people into our churches and preach the Gospel to them? Even if nine out of ten never return? That is what the church is for: to compel sinners to come in and hear the Gospel.
Churches who do not call sinners in are just as bad as churches who do not preach the Gospel.
One is a locked doorway, closed to those who need the message the most. The other is a hollow chamber, void of life to any who find themselves there.
Neither are acceptable nor laudable.