If footballers were paid less, then the extra money wouldnt magically end up in Africa, it would go to the owners and shareholders of the club. Given that top clubs are bringing in hundreds of millions of pounds in revenue, it is 'fairer' that this money goes to the players who are directly bringing in the money than to the businessmen who own the club (who are usually very wealthy already).
The percentage of revenue that players get is fair, the problem is that there is too much money in modern football, but if youre paying for Sky Sports/MUTV/etc then youre part of the problem.