"Caused" is different from "Coerced". Entrapment is where a LEO says "do this illegal activity or we'll do X", X being some relatively terrible thing. A LEO, even undercover, cannot put a gun to your head, tell you to do something illegal, and then arrest you for doing the illegal thing.
But more subtly, a LEO can't, for example, repeatedly ask you for drugs, and then when you finally find some to sell, convict you of distribution because you had exactly and only those drugs. However, if you're a drug dealer, if you've got more evidence of illegal activity than just what existed to satisfy the LEO's request, then entrapment may not be a defense.
And so here, in the indictment (http://cdn.arstechnica.net/wp-content/uploads/2014/11/williamsindictment.pdf), Williams is quoted as saying how many times he has exactly helped people lie to the federal government, which is a crime. The LEO did not make him do those things, and did not force or coerce him even to admit them.
Which is why entrapment is not a defense here.
IANAL. YMMV. BYOB.