Hi nemoayako,
Thank you for some interesting questions - I will try to answer but this is just my opinion so please seek other answers too. Apologies for a long answer but there are details to consider.
I think the reasons why specific links were chosen is known only to Apple and their business partners and I imagine it is confidential business information. Nevertheless, we can make educated guesses about why these corporations decided to make this arrangement. I am in the UK and unable to get background info on Japanese businesses so I cannot explain why allabout.co.jp was on your version of iOS7 but I can give some info about ESPN UK and I imagine that the UK arrangements and Japanese arrangements follow the same basic rationale.
I had never heard of ESPN UK before seeing the link on Safari. A bit of research told me that ESPN UK is owned by BT. This is a huge corporation - formerly telecommunications were owned by the British government but when Mrs Thatcher was Prime Minister of Great Britain in the 1980s she privatised all government assets she could and British Telecommunications became a private company, BT. It had a monopoly on telecommunications, owned all the telephone wires and switchboards. When the internet began it was based on 'dial-up services' using telephone wires and modems. Other companies wanting to offer internet access and/or telecommunications services had to pay BT a fee to use their infrastructure - BT grew very rich. But other companies were not willing to play this game for long and they invested in alternative infrastructure using e.g. satellites and dish receivers, fibre-optic cables etc. Customers opted into the new technologies and BT started to look 'past it', stuck with Victorian infrastructure, and no more monopoly. BT have tried to reclaim market share by also investing in new infrastructure (to offer super-high speed broadband). But as other UK companies such as Virgin or Sky already offer this, BT is in the position of being a late-comer trying to break into a mature market i.e. the days of easy profit are over. What all major UK ISP corporations are currently doing is accepting that technology is now the same for everyone so they can only win customers by competing on content. Currently, all major ISP corporations in the UK try to sign customers up for 'package deals' or 'bundles' which combine telephone services, internet access, and entertainment for one set price. BT, Sky, Virgin all offer television programmes, movies, sports channels. BT recently started to offer a BT Sports service which gives customers a chance to watch major soccer games. To promote their content and make their product look unique and attractive all major UK ISP corporations now run websites offering a magazine-style news and entertainment service which might look independent but exist to promote their television services. ESPN UK is BT's version of Yahoo, MSN, Google News. It is focused on sport because currently BT mainly offers sports programmes to its customers.
So much for background. If we ask why BT made a deal with Apple to get a link to ESPN UK into iOS7 then I think we can see it was in order to promote BT products and gain an edge over the major UK competitors like Sky and Virgin. Why did BT make this deal with Apple instead of Sky or Virgin? I think we can guess that BT is relatively struggling. It is a once-dominant corporation which has become old and is slipping behind more successful businesses. It needs to promote itself any way it can and the Apple deal, whatever it cost, must have looked like a necessary investment so BT was willing to pay more than Sky or Virgin (who are less in need of an Apple promo anyway) and Apple accepted the highest bid.
If you broaden focus and look at the other links supplied with Safari on iOS7, Apple, Disney and Yahoo, then I think you see a pattern. All of these are corporations which were once dominant, even had a kind of monopoly, but they have all taken a knock because other, newer, more successful corporations have taken a big chunk of their market share. Each of them are not in direct competition with each other so they can pull together for mutual help, and they are all dealing with essentially the same problem - how to grab back dominance in their marketplace or risk going under like IBM, Microsoft, Sony-Ericsson, Blackberry - so they can all agree one strategy and push it out on either a global stage (Apple, Disney, Yahoo) or locally (BT) depending on where their critical marketplace is located. Now, if this analysis is correct, we can assume that whoever owns allabout.co.jp is in the same situation as BT.
I hope this long answer has been useful. If I am right, we can understand not only why Apple put annoying icons on our browsers but also what that tells us about how confident these corporations are about their business standing - and thus whether we should not only buy their products but whether we should invest in their shares.
All best wishes, GrannySmith