The Bible does not call for, nor does it condone, slavery. The Bible also does not call for, nor does it condone, putting down women or treating them as inferior. The first people Jesus appeared to after his resurrection were women. That was purposeful.
That is not what the Bible calls for. Jesus said to give to Caesar what is Caesar's, and give to God what is God's. Does God want a government that supports the morals of the Bible? Absolutely. But that is because God knows what is right, and what is prosperous for the soul.
The issue is that people tend to attack the religion and the person. You don't call out one person who is saying something that you consider wrong. You make sweeping judgement against Christianity itself. Talking about corrupt institutions is pointless. Religious institutions aren't the only institutions with corruption. Corruption is everywhere, and it is because humanity is flawed and corrupt (aka, sinful). The entire message of the Bible is love. Jesus said that the greatest commandment is to love God, and the second-greatest commandment was to love others. There are people who will claim to be religious and will not adhere to these commandments. Until Jesus returns and Satan is locked away forever, this is going to occur.
As an aside, love doesn't mean letting people live the way they want to live. If a parent sees that a kid is engaging in bad behaviors, the parent will (or should) correct the kid. This usually isn't fun for the kid, but it's good for them. In the same vein, Christians are called to tell people about the Gospel (which is the Good News of Jesus Christ). It isn't our job to force our beliefs down their throats, but we are called to tell people so that they can have every opportunity to become saved. This requires telling them that they are sinners. This is taken as an insult by many people, but if you tell a liar that they are a liar, where is the insult?
We're all sinners. The Christian telling you that you're a sinner is also a sinner. They shouldn't be telling you this with an air of superiority. I, as a born-again Christian, am not better than you, as someone who doesn't believe in God. The job of a Christian isn't to fix non-Christians. It is to spread the message of the Gospel. The non-Christian can either accept Jesus, or reject Jesus. If they do accept him, it is the Holy Spirit's job to show this new Christian the areas where they need to change. I believe that homosexuality is a sin. I will never treat a homosexual like they are diseased. They are loved by God, which means that I need to love them as well. Their sin isn't somehow worse than my sin. The only difference between myself and a homosexual who doesn't believe in God, is that I have Jesus and they don't. I want them to know about Jesus and accept Jesus. Full stop. That is the entire purpose of Christianity. Love God. Love others.
Penn (from Penn and Teller) doesn't believe in God, but he appreciates evangelicals. At least, he appreciates evangelicals that are spreading a message in love, and not trying to browbeat someone (which is not what the Bible calls for). Something he said, which I love, is, "How much do you have to hate somebody to believe that everlasting life is possible and not tell them that? If I believed beyond a shadow of a doubt that a truck was coming at you and you didn’t believe it, and that truck was bearing down on you, there’s a certain point where I tackle you. And this is more important than that." He doesn't believe in God, but he appreciates the people who do believe, and who love others enough to tell them about Jesus. Again, not browbeating people. That's wrong, and that's not what Jesus did.