Can somebody explain what’s controversial here? Flynn got fired by Trump for lying about contacts with Russians. The FBI caught him lying to them which is a crime. Nobody forced him to lie. Flynn confessed to the crime.
Why is this an issue?
Because that isn't what happened.
The FBI was going to close the case on Flynn in January of 2017. They concluded that there was nothing wrong with what he did.
Then Comey and Struck decided to lay an entrapment sting on him. They even advised him that he needed no lawyer. They withheld exculpatory evidence from him and his lawyers.
Flynn confessed to lying in order to spare his son from the threats made to investigate him unless he did. Flynn did not confess because he was guilty of anything.
What isn't controversial about it.