For a long time law enforcement agencies from local police to the FBI use questionable tactics and are constitutionally allowed to lie to people to get what they need. This is not a new problem. But I would say if you don't commit crimes, and you don't lie to those asking you about it (in fact never speak to them at all without a lawyer) then you're probably ok. The burden of proof beyond a reasonable doubt lies on the state, so if they are making accusations that he lied, they better be able to prove it, or they look bad. Feds generally don't prosecute if they don't have a solid case.
Yes there are a lot of politically motivated people out there that think they will help their cause by saying things that aren't true. In America you can do that, just not under oath. If this guy said one thing, and the FBI can prove he said another under oath, then there isn't really anything sinister going on here and he's just screwed.