Flynn has a good argument that whatever lie he told the FBI is not material to the investigation of any crime. A lie has to be material to be criminal. If Flynn had baked beans for breakfast, and told the FBI he didn't, the lie is not material unless the investigation had something to do with baked beans.
We make points abut the niceties of criminal prosecution, evidence, presumption of innocence, etc. etc. — meanwhile the federal government routinely withholds evidence, violates the law, persecutes the citizenry, etc. etc.
Our entire government is staggeringly corrupt and needs to be dismantled and rebuilt along constitutional lines.
Trump appears to be making inroads in that direction. But there are many, many miles to go.