His buddies did a plea bargain (no doubt having the original charges lowered), but Swan went to trial, was convicted & was sentenced to 6 to 7? No surprise about the disparity in sentencing.
Byron York:
...Finally, Pickering got word from Civil Rights Division prosecutors, who said they had decided to drop the demand that Swan be given the five-year minimum portion of the recommended sentence. Pickering then sentenced Swan to 27 months in jail. At the sentencing hearing, Pickering told Swan, "You're going to the penitentiary because of what you did. And it's an area that we've got to stamp out; that we've got to learn to live, races among each other. And the type of conduct that you exhibited cannot and will not be tolerated....You did that which does hinder good race relations and was a despicable act....I would suggest to you that during the time you're in the prison that you do some reading on race relations and maintaining good race relations and how that can be done."
So Swan went to jail, for a bit more than two years rather than seven."