They're not targeting die hard UFC fans with events like this, they'll buy it regardless. They're targeting people who may not know about or are undecided about buying it. It's common in boxing and has been for years.
I can see why people don't like it but the UFC is a business and the more PPV sales for them the better, the best way to sell any fight it seems (Boxing, UFC, WWE) is by having the guys "hate" each other.
People will always jump on bandwagons for stuff like this. Its all marketing and as cringing as it might be it'll prove to be successful.