Jimmy Fallon was on point in his comedic portrayal of Ryan Lochte. This is to be expected of a former Saturday Night Live performer. Give credit where it's due. This ranks right up there with Tina Fey's portrayal of Sarah Palin as Presidential Candidate several years ago. Classic comedy at it's best with new material.
In the world of comedy, everything is fair game as long as it is funny. Ryan Lochte was on the world stage and he made no attempt to avoid interviews. He obviously lied to the public and the police so that opened the door for comedians to use his blunders as comedy material.
Nothing Fallon said about Lochte was untrue, it was just a bit exaggerated because that is the whole point of parody. If you are a public figure and decide to do childish things like get drunk, act like a fool, then lie about it...you deserve everything you get. Even Phelps, who was in the audience, laughed.
Ryan Lochte is a public figure who made a very big mistake in the public arena. As he willingly put himself in the position of being in the public eye, his actions are justifiably subject to scrutiny. Jimmy Fallon was simply pointing out the ridiculousness of Lochte's behavior and highlighting his manufactured image.