I don't know about you, but people have different expectations for different people; the guy that jokes around constantly will get a free pass because he's never serious and it's a waste of time to try to argue with him anyway. Well, at least I don't think there's a point in arguing with someone who isn't serious. It's basically the difference between a comedian telling offensive jokes and an average person doing the same, you don't take the comedian as seriously because it's just what the guy does- you don't have to like him though, you just don't respond because it's expected of the guy. You're the average guy, so everybody is surprised because you don't have a history of making offensive joke posts. Nobody is evaluating you on a double-standard because they're simultaneously taking your history into account when they're looking at that post or just moving on. You could probably say that the standard includes the personality of the person, nobody is unfairly evaluating you here.