II Thessalonians 2:11-12

We find that the man of sin's appearance will be with many signs. They will truly be astonishing performances—miracles—but all of his display of power will be for the purpose of deceiving. That can be translated to a deceit that originates in unrighteousness, the unrighteousness in the heart. The miracle is real but it is done to deceive. But the ones affected by this are the ones who are perishing. That is so interesting. Now why? Because they did not have a love of the truth. The true church is departing from it; the false church is ridiculing it. Those who are going to perish had truth available to them, but they didn't love it, that's the difference.

It means that from God's perspective, these people had the truth presented to them and they didn't love it. It does not mean that these people did not agree with it, it means that they didn't love it. What does it mean (in the light of that) when God gives them strong delusion? There are answers to this right in the scriptures; we'll just turn to one.