I'm not sure I see the difference. I also don't see how it applies here. "Otherwise wouldn't have committed" is key. The guy did this stuff routinely, even advertised it. This isn't a crime he otherwise wouldn't have committed. It just shouldn't be illegal at all.
What makes this fascinating to me is , since the undercover agents hadn't actually committed the crimes they told him, he wasn't, in fact, helping them lie to federal agents.
As the purported 'lie' was actually the truth, where is the crime?
Conspiracy. Intent goes a long way, especially in cases like this. Such as cases where FBI makes a fake bomb, ask suspect to flip this switch to arm it, ask suspect to place fake bomb at target, arrested for terrorism.