Still, IMO it is reasonable to bring that up as a character issue.
http://thecriminallawyer.tumblr.com/post/19810672629/12-i-wa...
In general, entrapment is when the police convince you to commit a crime that you wouldn't have committed otherwise. So, if you want to kill your wife, and your friend (FBI agent) happens to say one day, "Hey, I do a little killing on the side, just for gits and shiggles," and you hire him, that's not entrapment.
In contrast, if the agent is manipulating you and saying, "Hey, your wife is going to divorce you and take your stuff. Killing her is the only way to prevent ruin" and slowly convincing you to do it, then that's entrapment.
Bottom line: Already predisposed to doing the crime and probably would have gone through with it if it hadn't been the police? You're screwed. In contrast, if you're normally completely innocent and the person has to convince you to commit the crime, it's entrapment.
Basically, if the undercover cop suggests X and you say no. Then come on nobody will know, and you say no. And then they spend the next six weeks convincing you it's a good idea, then that's entrapment.
The issue is he was on a sting for over a year and that's plenty of time to cross the line.
Of note, asking several times and catching someone at a moment of weakness is not entrapment. So, if you have been clean for 10 years then you’re out of luck.
I suspect it's more likely they wanted to convict him on just the SR charges because that's better publicity, but it’s still odd.