Its an assumption
snootyfenooty that the club are protecting their brand now that we're in the Premier League. Why do i believe that the Premier League themselves are behind it? Purely because its not happened before with United and I know that this is right up the street of the Premier League.
Sure, you could be right that it could be entirely Sheffield United, doing this off their own back, but having spoken to someone at the club a month or so ago, he also mentioned that there was so much that United had to comply with commercially that everyone at the club was so busy... So why do this now? Its surely not a priority to go after an Independent Supporters group or a fan putting up some content that they've made themselves...