He makes a good general point, but what one thinks of someone switching clubs can depend on case to case concerning what was involved in such a decision, one can still judge if one sees anything hinky about it and question it or make fun of it. Lots of silly people out there who come off rather laughable, and that can include footie alliances and such like anything else.
For example, in another forum, know off a retarded troll who "used" to be a Juve fan when younger, and since then is a Roma fan (which I thank God for, I seriously couldnt take have anything in common with him), he admitted it several years ago, and was teased so much for it he refuses to acknowledge that was true since, really pathetically funny shit (since you post in XT, you might know this uber retarded very one of a kind moron, is called Capitan Totti).