It's simply because a lot of football fans are clueless sheep parroting what they read in their tabloid rag, what they hear on sky sports etc.
They think (insert any pundit you care to mention .. Paul Merson, Ian Wright, Stan Collymore, Redknapp, Charlie Nicholas etc etc the unending list of idiot football pundits) knows what he is on about and regurgitate their nonsense.
There is clearly an agenda against our manager within the media and the 'opinions' of these morons just echo it.