I think the difference between a player and normal work (such as a pub manager) is that the the assistant pub manager has not hapilly signed a long term contract which usually secures a hefty pay rise in the process. It has an end date at which the player can either renew with their existing club or seek an alternative with a signing on fee. It is all so geared up to the players these days and I think that this is the cause of the ill feeling when this sort of thing happens. A pub manager would simply serve notice in line with their contract and move on and has therefore not broken or attempted to break the agreement.
Or, as often happens, they have three months notice to serve and say "stuff that", I'm off up the road for more money. I just think we look at footballer's as our possessions and think they have the same feeling and allegiance to clubs as we do, they don't. The same can be said of people I send on training course, the contract ties them in for twelve months or they pay the money back, most get the training, gain more skills and want more money, of course, or leave.
We pay more to retain the better ones and others leave, as with football, if one of our guys said I want say £40k a year and I can only afford £35k, he'll go to a national company and get that sort of money, a footballer is no different and you or I wouldn't be either. They're not "judas", they're not "out for all the money they can get" but they have a short career and earning potential must be maximised during that period, that is always going to be improved by moving up the leagues.