He continued on with the intent to have sex with somebody he believed to be underage. That is a crime. It’s one thing to do it by accident or deception, but when he procedes to commit the act after becoming informed, well, it’s kind of like diving into a pool after being told the water was drained, it’s not going to end well.
Why would he believe them? They said they were 19, they change their story. They lose all credibility at that point. Why would anyone believe anything they say? How could a jury possibly believe anyone would believe anything they say after already lying like that?
Suppose the guy that meets up with the fake fifteen year old lies and says he is 21 but he’s actually fifteen. Should the cop be charged with soliciting a minor?