You do realize there are fans who have supported clubs like Man U for generations in their family? You make it sound like it just changing a brand of underwear. Players are fans of the game too and have been in this for their whole lives, so if some of them are against something this drastic, they have legimate claim to voice it. Without being mocked for it, for the statement of "football is nothing without fans". I mean really? Thats what triggers a football "fan"?
But you are right, if they dont like it, they will stop following. And thats defenitely not gonna be a good thing for this overly greedy venture.