It doesn't matter if they're falling for bait, because they essentially have broken the law. Let's say I give you a gun, and the option to walk away or kill someone. I tell you there will be no consequences to you if you pull the trigger, but that the gun is loaded, and obviously deadly to the person. I do not tell you that I am an actor working for the police. The gun is actually empty. If you pull the trigger, you are a murderer because you committed an act with intent to kill someone by your own free will, even if you were baited to attempt to kill someone, but never ended up killing them.
The same applies to these pedophiles. They are flirting, talking dirty, and eventually driving to these decoys' houses, pulling the metaphorical trigger that would lead to the crime of them having illegal sex. This makes them sexual predators. Even if they were deceived into the situation, they were not forced to make the choice. They were offered a choice to either have sex with a minor or ignore the minor, and they chose to have illegal sex.