There will always be people who talk authoritatively about God's will but have no idea what the Bible says. Many people engage their mouth well before they engage their brain. People merely parrot what they have heard others say. Some have never considered the implications of their words. Something that sounds good is not necessarily something that IS good.
Most deception comes in brightly colored packages.
We must see beyond the polished words and slick presentation. Most Deception minimizes or seeks to eliminate any talk of sin and responsibility. Deceivers will diminish the character and person of Christ. They may talk about how much they love Jesus, but if you ask them to describe Jesus you will get a different picture. Sure, at first they will say, He is the Son of God and Savior.