If someone is pro-abortion, pro-sexual perversion, and covets other people's money and possessions, then I would say they are NOT Christians. They can deceieve themselves however they like.
God's Word is true, and the final authority.
Abortion: (Jeremiah 1:5, Psalm 139:13-16)
Homosexuality: (Romans 1:26-28, 1 Timothy 1:8-11)
Coveting: (Exodus 20:17, 1 Timothy 6:10, Deuteronomy 5:21)
As for people who demand to label themselves as Christians, but they do not follow God's Word, don't care what Christ said, and don't live according to Spirt, they should read these chilling words from Christ Himself:
"Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven."
Matthew 7:21
Tell _them_ that.
There are millions of them out there...