Not to lewdness.
Don't you know that yet?
The purpose of these stings is not throw these pervs in jail, it is to stop the lewd behavior in the public bathrooms. Why did the good Senator go out of his way to this particular bathroom, passing through security checks unless he knew it was a known cruising zone?
You said he was not a crook. He pled guilty to a crime. Therefore he is a crook. In the post you cited, I did not say what he pled guilty to, nor does it matter much.