Just like Adam was tempted by the apple, we sometimes get lured by poisonous ideas or people. Sometimes those people and ideas are tempting. Tempting to taste the fruit, and lured by their charm.
Fool me once shame on thee, fool me again, shame on me.
It’s okay for us to be fooled. Poisonous thoughts and people are typically manipulative, and they do not change. They will claim they have changed, but that is typically their poison being masked as harmless. It never is. Move on. Stay away.