How Can So Many Professing Christians Support Things That Are Anti-Christian?

Questions about how so many professing Christians can support things that are anti-Christian, such as LGBTQ issues and abortion on demand, and how to work with Christians who have views that seem to contradict things stated in the Bible.

• How can so many professing Christians support things that are clearly anti-Christian, such as LGBTQ issues and abortion on demand? Are they really believers?
• How do you work with Christians who have views that oppose the Christian faith and seem to contradict things stated in the Bible, especially if they are close friends?