I did what I could to check it out.
Kaylon Johnson was beat up, and likely robbed. An arrest was made. I found nothing about any conviction.
Best bet: Johnson was robbed, and blamed it on racism.
If there had been a conviction, it would have been in the news for years.
http://www.ksla.com/story/9479629/update-longview-man-arrested-accused-of-beating-obama-supporter
There have been several cases of "lie"berals who fell down drunk and then blamed some mysterious bigot for their bruises.
You are right though. Nothing but that story. No court documents or anything.