Even if he wasn't guilty of chanting (although come on, he probably was wasn't he) - he is certainly guilty of not standing up for the black bloke and helping him on to the carriage.
And then what, get his head kicked in as well? Jesus wept mate get a grip. It could so easily have been you or anyone stood in that carriage adjacent to a few idiots, I certainly have been following Brighton throughout the years. Adjacency isn't a crime.