I'd be absolutely astonished if Webb is or ever has taken a real actual bribe. But I do think Sky tends to hype decisions in Utd games more than they do for other clubs, I think they give Fungus' moans plenty of sympathetic air time, I do think that a ref's life is made much easier if he makes sure he's a lot MORE 'sure' when giving opposition fouls, cards etc than he needs to be when giving them to Utd. Indeed several ex refs have come out and said exactly that, that if you get a decision wrong against Utd there are consequences, so you make yourself a lot more 'sure' next time. The same will likely apply in terms of the FA picking refs for Utd fixtures.
Wasn't it Kafka who said something along the lines of 'the most dangerous censor is the one in our own head'? It's a similar mechanic to what happens in football, and it happens in the rest of the media too. It would be staggeringly naive to think that football isn't subject to the same kinds of pressures as other areas of the media, the same kind of commercial imperatives, and those biases favour Utd in football for similar reasons that they favour US/UK interests in the media...largely because it's safe and it pays.
PS
Well in Babel.