He doesnt like the fact that khan gets paid more then him, bigger fanbase and generally well known by everyone in the UK.
Froch gets alot of hate even in his hometown, he didnt even get to rep his town holding the olypic tourch!
His awful attempts to call out calzaghe is what most people associate him with.
The papers hardly mentioned the bute win but you can bet khan gets mentioned fighting a club fighter.
Pure and simple jealousy.