He probably has a pretty good case given that.
That he was not in uniform, not on his employer’s property, and not on duty says a great deal. Not only that he isn’t even recognizable as a transit employee.
To permit him to be fired for expressing himself on his own time is to make all of us subject to the whim of those with authority over any area of our life.
Had he worked for a private employer, even disregarding civil rights laws, this man would have a case against them for injuring him without just cause.