Since local or state don't prosecute securities violations, yeah, I guess your right. But there are perjuries that can be committed at the local level, depending on the jurisdiction. Don't assume you can blow smoke and get away with it.
It's not just those feds. Lying to the FBI is a very bad idea. And even if you're guilty of something, they may let it go if it's not their focus. When the feds were first looking for the source of recreational drugs found by the postal service, they interviewed recipients. And as I recall, they didn't prosecute many (any?) of them. Or at least, not end users.
