Why would the FA 'investigate' Webb ffs?
What they, or someone should do is not specifically investigate Webb but to investigate bias in reffing decisions full stop. It's perfectly possible to research it and get proper hard data.
Because while it's fair to say that EVERY club thinks the media and refs hate them, and while I think it's also fair to say that the bigger the club, (or rather the bigger the club's rep and home support) the more decisions go it's way at home, and I also think it's fair to say that high profile English players also get favoured by refs, I also think it's telling that basically every club see things as biased towards Man Utd. Spurs fans, Arsenal fans, Wolves fans - sure they'll moan about their own club, and probably certain clubs and rival clubs, but EVERYONE sees an issue with Man Utd.
For example, I think it's telling that when Rafa, who basically thanks to the media is generally mocked and seen as a total clown by the vast majority of general fans (as far as I can tell) actually stood up and attacked Fungus, that's also the ONE time I can remember fans in general being in complete agreement with him and generally saying stuff like 'good on him' etc etc.
I'll even go further than that.
Given the money in the game, given that Sky are LEGALLY REQUIRED to maximise their profits, and given that Man Utd are the most popular club domestically and probably even more importantly worldwide, it would in fact be naive to think that there's no bias of any kind in their favour.
It is absolutely 100% in Sky's commercial interest for Man Utd to be successful, for their rep to be played up, for that club to be glorified and the manager and players feted and hyped, and for their stars to be on the pitch as often as possible. Man Utd sell more subscriptions, set top boxes, HD upgrades and fucking 3d glasses than any other club in England. Looking at it cold heartedly, if Sky weren't using Man Utd as a means by which to maximise profits then their execs and shareholders should be asking questions.
It's not all down to Sky by any means, but it also isn't a pure coincidence that the Man Utd years have also been the Sky years. It also isn't a coincidence, or just down to tactics alone (though that is probably the main reason) that Utd have been relatively shit on the continental stage, considering the number of chances they've had and the amount of cash they've thrown at the problem.