Let's be clear. The crime was "thinking" that the person was a minor. They did not KNOW, nor could they KNOW, how old the person was.
Ironically, if a 13-year-old went on an adults-only chat room and posed as a 20-year-old, no adult would be arrested. Where an actual child IS harmed, everyone looks away.
No. Their crime was soliciting sex from someone they thought was a minor. That's a big difference.