Conservatives, for sure, need to be more open-minded. That's what gets them into trouble. An open-mindedness isn't the same as telling them they're wrong.
The issue is whether or not what one person thinks is sinful isn't necessarily what another thinks is sinful. No Christian, liberal or conservative, should condone sin. Sin is sin. We should "hate" the sin, not the person. God hates sin but He doesn't hate His children. That's why Jesus came, to reconcile that.
A person is a person. You cannot fault a person for who they are, what they believe, or who they feel they are. You cannot say a person isn't a person because they adhere to the way their bodies function. Everyone is a sinner. Everyone falls short of the glory of God. And salvation isn't instantaneous. It is a lifelong journey; it is a journey toward perfect love. For sure, no one is perfect. But I think we need to stop debating what the Bible means to say and focus on what it actually says: that through Jesus, and Jesus only, do we achieve salvation. We need to focus on working out our own salvation and not worry about petty arguments that will only continue to divide the church.