First of all, he's innocent until proven guilty. Maybe he did not see the age in the profile and thought he was dealing with an adult. Maybe he saw the age, but thought it was an adult role playing a little girl. That sort of thing happens a lot on the internets. Heck, there are whole web sites where you can have virtual sex with other ponies, and I'd be willing to bet there are no real horses involved.
There was no victim. I repeat, there was no fourteen year old girl. There was a cop, posing as a fourteen year old girl. If Doyle thought he was talking to an adult role playing a teenager, he would have been right.
If we accept this sort of entrapment for sex offenders, 'national security' will be next. Before long there may be FBI agents trolling the internets saying what a good idea it might be to disrupt presidential appearances, so that they can arrest anyone who agrees. The bottom line is that Brian Doyle deserves the full protection of the constitution and the law, because if he doesn't get it, nobody does.