'I would substitute 'success' with 'greed' in this case.'
A private business has decided that it makes commercial sense for it to pay Farah to appear. What is greedy about him accepting the offer?
You're demonstrating the point perfectly. The British way is to be jealous of someone else's success and try and bring them down as a result instead of saying 'Well done' or even 'If I work as hard as that at what I do, maybe I'll be successful'.
I would be more inclined to question the nature of the race itself. I think the large majority of participants are amateur runners, running for no personal gain other than the achievement itself. And yet there are professional athletes taking part for financial gain. It's one thing to offer a prize for the winners, thats the nature of competition, but quite a different thing to be paid just for appearing.
These days, there are a lot of marathons and they compete to attract the star names.
Having star names attracts sponsors. Having sponsors increases the resources available to the organisers and allows more runners to take part. More runners means more charity fundraisers and more funds raised for charity.
One of the main reasons for the success of the London Marathon has been the way it has been marketed - partly by getting famous runners to take part. They've taken part because they've been paid to do so, and their participation has made the London Marathon into the world's biggest and best known.
Mo Farah has a talent, and he's profiting from it - I see nothing wrong with that at all. It happens in all fields of human endeavour, and in most countries it's admired.
You make it sound as though Mo Farah blackmailed the London Marathon into including him.
If a business organisation came to you and said, in effect, our business plan shows that we can get a net benefit by paying you £x to do this would you really say you'd like to do it for free?
Referring to the London Marathon as a charity may be strictly true but its charitable status is more to do with not having to pay any tax than actually being a 'charity'. Take a look at this summary of its finances. So, inferring that taking money from a charity is somehow depriving the poor is mischaracterising the situation.
Incidentally, 'opening shops' is not an option. The huge successes in 2012 have resulted in an over-supply in the personal appearance market and even gold medallists are finding it hard to earn money that way.